Planned Out: The Discriminatory Effects of Planning’s Regulation of Small Houses in Multiple Occupation in England

Abstract Some claim that planning has a “dark” side which is expressed in policies and practices that disadvantage minorities and less powerful groups. This article explores how revisions to an aspect of English planning legislation, plus the linked adoption by local planning authorities of “restrictive” development policies, may disproportionately affect the housing choices of young, lower-income adults. Combining documentary research, secondary data analysis and Yiftachel’s conceptual framework of “planning as social control,” it examines how the legislation and policy might limit the supply of an accommodation type popular with this group, and the resulting social, political and economic effects. The implications for planning theory and practice are considered.


Introduction
Some claim that planning and land-use regulation have a "negative" (Finkler & Grant, 2011) or "dark" (Yiftachel, 1998) side that finds expression in policies and practices that disadvantage, exclude, control and/or oppress minorities and less powerful groups (Flyvbjerg, 1996;Yiftachel, 1998Yiftachel, , 2000Yiftachel, , 2001. Studies assert evidence of planning's bias against various groups, including minority ethnic communities (Maldonado, 2017), women (Ortiz Escalante & Valdivia, 2015) and disabled people (Finkler & Grant, 2011), arguing that this is achieved via overt tactics, although more commonly through subtle, benign, "facially neutral" measures (Maldonado, 2017(Maldonado, , p. 2643. With global movements like Black Lives Matter and Me Too focusing renewed attention on inequalities and injustices in established institutions and social practices, now is a timely moment to examine further the possible discriminatory effects of institutions of spatial regulation.
Studies in various countries, including Canada (Finkler & Grant, 2011), Denmark (Flyvbjerg, 1998), Israel (Yiftachel, 2000(Yiftachel, , 2010, and the United States (Maldonado, 2017), propose evidence of planning's "dark" side. Expanding the geographic scope of this literature, the study reported here focused on England's planning system. It employed Yiftachel's (1998Yiftachel's ( , 2000 conceptual framework of "planning as social control," an original and systematic mechanism for considering planning's influence across multiple domains, to examine the possible discriminatory effects of planning's regulation of small shared houses. Attention focused on the potential disproportionate

Small Shared Houses and the English Planning System
In England, The Town and Country Planning (Use Classes) Order (2010) specifies "classes of use" of buildings and land. It was revised in 2010 to introduce a new use class, Class C4houses in multiple occupation. This class covers shared houses occupied by between three and six unrelated individuals as their only or main residence, who live as two or more households, and who share certain basic amenities, such as a kitchen. The creation of the new use class came in the wake of a 2008 Government commissioned evidence review that examined the impacts of shared houses, or houses in multiple occupation (HMOs), and planning's possible approach to these properties. This evidence review was itself prompted by lobbying from residents on the perceived problem of high concentrations of HMOs (ECOTEC, 2008). A public consultation on planning's approach to HMOs followed the evidence review (DCLG, 2009) and found that respondents favoured the introduction of the new use class (DCLG, 2010b;Wilson, 2017).
A further aspect of planning legislation, The Town and Country Planning (General Permitted Development) Order (1995), from here on the GPDO, was also amended in 2010. The revisions granted permitted development rights to allow change of use, without the need for planning permission, between Class C4 houses in multiple occupation and Class C3 dwellinghouses. Class C3 dwellinghouses refers to use as a dwelling house by an individual, by people living together as a family, or by up to six individuals living together as a single household (Wilson, 2017). While introducing the new right, the GPDO also provides the legal basis for its withdrawal. An Article 4 Direction, itself a poorly studied planning instrument (Larkham & Chapman, 1996), made under the Order, allows the Secretary of State or a local planning authority to withdraw permitted development rights in a defined area (Ministry of Housing, Communities & Local Government [MHCLG], 2020). The instrument, coupled with the creation of a new use class covering small HMOs, has provided local planning authorities with the power to enact policies that tightly control the provision, through change of use development, of small shared houses. 1 Only Layard (2012) appears to have investigated the possible discriminatory effects of these legislative and policy developments, and her analysis had a particular focusthe importance of conceptualisations of the "local" in shaping responses to HMOs.
The "Problem" of Multi-Occupancy Housing England's recent efforts to actively manage shared houses through planning legislation and policy connects to a long tradition, evident in the UK and elsewhere, of viewing multi-occupancy properties as problematic and in need of control (Grant et al., 2019). From lodging houses (Morrell, 1967) and single-room occupancy hotels (Mifflin & Wilton, 2005) to HMOs (Hubbard, 2008;Wakelin, 1968), halfway houses, shelters (Lauber, 1996) and group homes (Finkler & Grant, 2011), multi-occupancy accommodation has troubled policymakers, reflecting wider societal anxieties about this type of property and its occupants (Frisch, 2002;Grant et al., 2019). In mid-C19th Britain, for instance, common lodging houses, which provided cheap rooms for migrant workers, were widely perceived as poor quality and overcrowded propagators of disease, poverty and crime (Morrell, 1967). Responding to such concerns, the Common Lodging Houses Acts of the 1850s introduced new rules on the operation of these establishments and gave new powers to local authorities over their management (Crook, 2008). Communities today, in the UK and elsewhere, continue to express worries about all forms of multi-occupancy housing (Grant et al., 2019). HMOs have emerged as a contemporary concern. Residents are vocal critics of the quality, maintenance and cleanliness of HMOs, the perceived impact of HMOs on the amenity, character and cohesion of a neighbourhood, and the behaviour of HMO occupants (Brookfield, 2019;Sage et al., 2012aSage et al., , 2012b. Shared student properties have usually been the target of criticism, as evidenced in the UK (Allinson, 2006;Smith, 2008;Hubbard, 2008), Canada (Revington et al., 2020), Spain (Garmendia et al., 2012) and China (Gu & Smith, 2020). However, in England, shared properties occupied by benefit claimants and migrant workers have also attracted complaint (Smith, 2012). Consequently, planning systems have introduced measures, often at the local level, that tightly control the distribution of shared houses (Layard, 2012;Revington et al., 2020;Salkin & Levine, 2010). As a result, the housing choices of those who rely upon shared accommodation are constrained in ways not experienced by other groups (Hubbard, 2008;Layard, 2012). Despite the potential for these planning measures to disadvantage and exclude, they have rarely been a focus of study.
The "Dark" Side of Planning Planning's "dark" side is said to manifest in a bias against minorities and other less powerful groups in both the planning of environments and in the embedding of oppressive and exclusionary principles and practices in the planning system (Lennon & Fox-Rogers, 2017). Seldom are these positions displayed openly (Yiftachel, 2001). Instead, seemingly neutral (Maldonado, 2017(Maldonado, , p. 2643, sometimes even progressive (Finkler & Grant, 2011), measures are seen to operate to promote the interests of powerful groups. Even those implementing these biased measures may be unaware of their "regressive consequences" (Yiftachel, 2001, p. 11). Examples of planning's dark side are identified across multiple countries with the scale of disadvantage advanced, and the explicitness of the bias shown, varying between and within planning systems (Allmendinger & Gunder, 2005). Informed by Marxist, neo-Marxist, feminist, postmodern and post-structuralist schools of thought, studies have proposed that planning demonstrates partiality against, amongst others, minority ethnic communities (Maldonado, 2017;Mandelker, 1977), low-income groups (Atkinson, 2004), women (Ortiz Escalante & Valdivia, 2015, LGBTQ communities (Frisch, 2002), disabled people (Finkler & Grant, 2011), homeless and migrant communities (Levine Einstein, 2021) and traveller-gypsies (Ellis & McWhirter, 2008). Planning is seen to deliver outcomes that disproportionately disadvantage these groups. For example, Maldonado (2017) argues that narrow definitions of a "family," which focus on "immediate relatives" and which are employed in some single-family zoning districts in North America, can disproportionately disadvantage minority ethnic communities who may be more likely to demonstrate living arrangements that depart from the definition.
Not everyone subscribes to the view, however, that planning has a dark side. Yiftachel (2001) claims this assessment of planning is still relatively rare in the planning literature. Many scholars are, he argues, wedded to the view that planning is a force for good with any policy failures attributed to external political, social and economic forces. Others, though, directly critique the notion of a dark side. Notably, Allmendinger and Gunder (2005), employing Lacanian and Derridean perspectives, and linking to Gunder (2003), Gunder and Hillier (2004) and Gunder (2003, 2005), reject Yiftachel's position whilst claiming it is theoretically underdeveloped. Following Gunder and Hillier (2004), they argue that "dysfunctional behaviours," like repression and favouritism, can occur in planning but are most likely a consequence of planners seeking to implement planning regulations while conforming to what they believe are professional and societal expectations of plannersthey are less likely to be due to any intentional and systematic bias against certain groups. For example, in pluralistic societies where multiple competing interests meet in planning decisions, planners, following perceived professional and societal expectations, try to accommodate differing positions and concerns, yet their decisions are unlikely to benefit and satisfy all equally. Further, in some situations powerful groups may "hijack" the decision-making process, resulting in outcomes that better serve their interests. Such "unintentional" advantaging of interests within planning, which may in each instance be viewed as progressive or regressive, depending upon the standpoint taken, does not, in Allmendinger and Gunder's (2005) view, constitute a dark side. However, they claim it would be identified as such under the current dark side discourse. In their opinion, there needs to be "systematic and procedural prejudice" in planning for a dark side to be identified (Allmendinger & Gunder, 2005, p. 105). Yiftachel (1998Yiftachel ( , 2000Yiftachel ( , 2020 has been key in developing the dark side discourse in the planning literature, arguing that systems of land use regulation can oppress peripheral groups by operating as instruments of social control; although he also notes they can be tools of "emancipatory reform." By "the stroke of a pen," he argues that planning and development policies "secure, ignore or ruin" communities (Yiftachel, 2020, p. 162). Operating through four interconnected dimensionsterritorial, procedural, socioeconomic and culturalplanning can exert "oppressive control" over less powerful groups while securing the advantages of powerful groups (Yiftachel, 1998). In contrast to scholars like Levine Einstein (2021) who argue that the advocates of exclusionary planning measures both know and support their discriminatory effects, Yiftachel (2001) suggests that this oppression is not necessarily a conscious act. Rather, it might be the result of actors operating on a broadly shared set of understandings that typically work in the favour of more powerful groups. However, he does see oppressive control as squarely intentional in some contexts (see Yiftachel, 2009aYiftachel, , 2009bYiftachel, , 2010Yiftachel, , 2015Yiftachel, , 2020.

Planning and Social Control
The territorial dimension in Yiftachel's (1998) conceptual framework refers to the control of space achieved through measures such as containment, surveillance and segregation. In urban areas, control is demonstrated through land use and housing policies, like zoning ordinances in North America that segregate, usually on the basis of ethnicity, race and/or class. The procedural dimension encompasses all aspects of the creation and implementation processes of plans and policies. It covers the whole policy process, including the formal decision-making arena, relationships between planning authorities and communities, public participation, the provision of information and so on; and the potential for these items to marginalise and exclude less powerful groups. The socio-economic dimension covers planning's long-term effects on social and economic relations (Yiftachel, 1998, p. 402). Land use policies introduce and distribute social and economic costs and benefits associated with development both across and within communities. Yiftachel argues that planning supports the interests of elites by skewing benefits towards powerful groups while directing costs towards the less powerful. This sustains and even widens inequalities and fosters deprivation and dependence amongst less powerful groups. Finally, the cultural dimension concerns planning's impacts on the collective identities and cultures found within a territory (Yiftachel, 1998, p. 403). Land use policies have an important influence on the expression or oppression of cultures and identities. Policies on settlement patterns, the location of housing and services, and the qualities and norms of public spaces can promote a homogenising process, and the reduction of cultural diversity, or a pluralistic approach that respects difference (Yiftachel, 1998, p. 403).

Methods
A mixed-methods approach, involving documentary research (Denscombe, 2017) and secondary data analysis of HMO and student household data, was used to investigate the content of England's revised Use Classes Order, the local planning policy and practices it has enabled, and the possible discriminatory effects of these items. The research was completed between December 2019 and June 2020 and reflects the policy and legislative positions in place at that time. Over 300 electronic documents in the public domain, which provided the greatest insight into the legislation and the linked policy and practice, were retrieved for analysis from online repositories including the UK Government's main website (gov.uk) and the websites of multiple local planning authorities. Documents included Acts of Parliament, Statutory Instruments, national planning policy and guidance (chiefly the National Planning Policy Framework (NPPF), National Planning Practice Guidance and Circulars), government-commissioned research and consultations, and Decision Letters from the Planning Inspectorate. Documents also included relevant Article 4 Directions (and supporting materials such as background research reports and Equality Impact Assessments), Core Strategies, Local Plans, Supplementary Planning Guidance and Supplementary Planning Documents produced by 43 local planning authorities. These 43 authorities (see Table 1) all ranked in the top 20 authorities in England on one or more of six interrelated measures: total number of HMOs; percentage of all dwellings estimated to be HMOs; total number of student households; percentage of all households estimated to be student households; number of Output Areas where 10% or more of households are student households, and percentage of Output Areas where 10% or more of all households are student households. Local authorities that scored highly on these measures were thought particularly likely to have policy and practices in place to manage HMOs as they were assumed to have potentially sizable populations of HMOs to manage. Consequently, it was assumed that a focus on these authorities would maximise opportunities to learn about planning's approach to small shared houses (Stake, 1995). A 10% threshold was used in the measures because this figure has gained traction amongst many local planning authorities as a marker of balance within a community, in respect of the presence of student households and HMOs (a point returned to later). Student household data were derived from the Census 2011. HMO estimates were derived from Local Authority Housing Statistics data returns (England 2017-2018) (MHCLG, 2019). These returns may underestimate HMO numbers as there are known difficulties in establishing an accurate picture of the size of the HMO sector (Doyle, 2018;Smith 2012). Data were analysed in Excel. With the methods explained, discussion now turns to the results.

National Legislation as "Regulatory Gymnastics"
A certain amount of "regulatory gymnastics" seems to characterise the approach of the revised Use Classes Order (from here on "the Order") to the creation of a new use class that covers small numbers of unrelated people sharing a home. In the Order, household arrangements that seem quite dissimilar are viewed as similar. Occupation of a dwelling by either a small religious community or a family is assumed, for instance, to be equivalent in use and impact as both are captured in Class C3 dwellinghouses (DCLG, 2010c). Conversely, distinctions are drawn between household arrangements that present no material difference in use or impact. Indeed, Circular 08/2010which was issued in 2010 (withdrawn in 2014) by Government and which provided non-statutory guidance on, amongst other matters, Class C4explains that the new class effectively re-assigned development formerly located under Class C3 (DCLG, 2010c). Class C4 does not then capture a new, qualitatively different use. The Order's unique understanding of a single household enables it to find difference where there appears to be none. Living arrangements that would ordinarily suggest a single household, have been judged as such by the Courts (Waterson and Lee, 2000) and can be alluded to as such in local planning policy, with Nottingham City Council (2020, p. 96), for instance, noting that "returning students have a preference to live as a household with friends" (emphasis added), are classed within the Order as 'multiple households' and are located in Class C4. The Order perceives a single household to be where people in a dwelling house are connected through family, religious, employment, caring or landlord-lodger relationships, but not where the relationship is one of friendship or simple cohabitation (DCLG, 2010c). However, these latter relationships seem more likely to produce an authentic manifestation of a single household than might a landlord-lodger relationship or an employer living with domestic staff. Housemates may occupy a property in ways similar to a family, with occupants cooking, eating and relaxing together. A couple renting a property with a close friend might be expected to occupy it in much the same fashion as would a couple renting a property with one partner's sibling, yet the revised Order would only consider the latter a single household (Oxford . The deliberate and exacting approach taken to the structuring of the definition of a "single household" in the Order has echoes of the deliberate and exacting approach taken to the structuring of the definition of a "family" in some zoning ordinances in North America (Maldonado, 2017;Salkin & Levine, 2010).

Local Regulation as Exclusion and Control
Of the 43 local planning authorities included in the study, 31 or 72%, had an Article 4 Direction in place that suspends permitted development rights for change of use from C3 dwellinghouse to C4 houses in multiple occupation (from here on, "a Direction"). Two authorities had made a non-immediate Direction (Table 1). Ten (23%) local planning authorities had no Direction in place (Table 1). The following discussion largely focuses on the 31 authorities with an implemented Direction. Of those 31 authorities, for a slim majority (16 or 52%) the Direction covered the whole administrative area (Table 1). For the remaining 15 authorities, one or more Directions covered parts of the administrative area. This could range from an individual street to multiple electoral wards, to a community's entire built-up area.
The two areas with non-immediate Directions both intended, at the time of the study, district-wide Directions. Across authorities, there is a trend towards widening the area covered by a Direction. For example, one or more Directions initially covered specific neighbourhoods in Birmingham and Brighton and Hove but these were supplanted by district-wide Directions, while in Reading and Durham additional Directions covering further neighbourhoods have been introduced over the years. Using Article 4 Directions to suspend permitted development rights across an entire administrative area should not be the norm, according to national policy and guidance. There has to be "a particularly strong justification" for the withdrawal of permitted development rights across "a wide area," while Directions should "apply to the smallest geographical area possible" (MHCLG, 2021, para. 38). A strong justification for the district-wide approach practised by most of the authorities in the sample seemed absent in some cases. Often it was argued that applying the Direction to only selected areas would simply transplant the issue of HMO conversions to other neighbourhoods. Whether all neighbourhoods form appealing, affordable and viable markets for HMO conversions is, however, debateable: a point alluded to in supporting material for Sheffield's spatially-targeted Direction (Sheffield City Council, n.d.). HMOs are typically clustered in discrete areas near places of study or work that respond, at least in part, to occupants' locational preferences (Brookfield, 2019;Kinton et al., 2018). The consequence of local planning authorities favouring district-wide Directions is that the provision of small shared houses across many entire towns and cities in England is tightly controlled. Although Government and local planning authorities acknowledge that HMOs provide accommodation "for people whose housing options are limited" (DCLG, 2017, p. 4), the blanket nature of these measures constrains options further.
Planning authorities with Directions in place have either adopted a discrete HMO development policy to determine applications for HMO conversions, or have created policies that cover HMO development alongside other specialist housing, such as purpose-built student accommodation. Common to many approaches is the use of a threshold whereby applications will be refused if more than a specified percentage of properties in the surrounding area are already in HMO use. Conversely, in a couple of authorities HMO conversions are supported in areas with very high concentrations of HMOs. Additional conversions in these locations are supported because they are considered unlikely to cause further "harm." An explicit threshold approach, in draft or adopted form, is found in around 65% of the authorities with a Direction (Table 1). Authorities without this explicit approach often set out a requirement to avoid "over concentrations" or "damaging concentrations" of HMOs, although fail to specify the proportion/number of HMOs necessary to realise these scenarios. Thresholds are usually set at 10%, 20% or 25%. The area considered when applying the threshold ranges widely from a tight 40 m radius around the applicant property to an expansive local area capturing the "home" Output Area of the applicant property and all contiguous Output Areas.
An influential report, "Balanced Communities and Studentification: Problems and Solutions," by the interest group The National HMO Lobby (2008), which consists of over 50 residents' groups, has seemingly been key in establishing interest in the concept of a threshold amongst local planning authorities. Some authorities even cite the report in the background documents associated with their HMO conversion policies. The report argues that when HMOs exceed 10% of properties, or HMO occupants comprise more than 20% of the population, an area "tips" from being "balanced" to "unbalanced." "Unbalanced" communities are identified as unsustainable and prone to "rising problems and declining community" (National HMO Lobby, 2008, p. 5). Focusing on household types, and referring to household composition data from the 2006/07 Survey of English Housing (preliminary data), the report claims that a balanced community consists of not less than 60% families, not more than 33% single-person households, and not more than 10% HMOs (National HMO Lobby, 2008, p. 6). These proportions were chosen because they approximated England's national household profile in 2006/07, interpreted by the Lobby as constituting a set of "national demographic norms" that should be protected (National HMO Lobby, 2008, p. 6). For the Lobby, the fact that HMOs accounted for, on average, 7% of households in England in 2006/07 justified limiting HMOs, allowing for some deviation from this "norm," to less than 10% of properties in local communities. In presenting this norm, however, it advised that the intention is not to specify that all communities should reflect it while it also suggested that different norms will be relevant in different contexts. The Lobby's construct of a 10% threshold and tipping point proves not, then, to be the product of an assessment of the relative impacts of different concentrations of HMOs. Rather, it is the product of a simple assessment of England's household mix in 2006/7. Local planning authorities often appear to adopt a similar approach to selecting a threshold. Planning authorities do not generally present evidence of the possible impacts of one threshold relative to another. Instead, assessments of an area's household mix, at a given point in time, often underpin decisions on the chosen threshold. For some authorities, no obvious evidence is presented for the selected threshold, or the evidence presented implies that an alternative threshold could have been chosen. For example, a study commissioned by Manchester City Council (2012, p. 125) concluded that a 20% threshold of HMOs could form a tipping point within the city, but advised that it would be difficult to set any citywide HMO threshold given the differing capacities of individual neighbourhoods to accommodate these properties. The city's Core Strategy, however, outlined an interest in a 10% threshold and the intention of preparing additional policy on HMOs that adopts a threshold approach.
To operationalise their HMO threshold policies, local planning authorities detail various ways in which they will assess the proportion of HMOs within an area. Commonly reported methods include checks of registers of licensed HMOs, of records of properties with C4/Sui Generis HMO planning consent and of Council Tax data. On this latter item, many authorities examine if dwellings near to an applicant property are exempt from paying Council Tax because all occupants are recorded as full-time students. Other authorities talk more generally about employing Council Tax data to develop a baseline understanding of HMO concentrations in their areas. Besides student exemptions, Lincoln uses Council Tax data on benefit claimants to determine the location of HMOs (City of Lincoln Council, 2019). Through these practices, it would seem that data on the geography of particular groups (students and benefit claimants) are effectively used to limit the presence of these groups by limiting the provision of the kinds of shared properties the groups rely upon.
The concern for student households observed in the application of HMO threshold policies was replicated across local authorities' wider approaches to HMOs. Authorities frequently identified students as "problematic" occupiers of HMOs, reflecting the widely reported views of longterm residents (see Brookfield 2019;Munro & Livingston, 2012;Smith, 2008). Policies regularly commented on the potential for students to negatively affect residential amenity and community cohesion through noise, anti-social behaviour, littering, poor waste management, greater comings and goings at properties, population "churn," and inconsiderate parking. The emphasis on students found in local planning policy is reflected at the national level. Indeed, contributors from coastal areas to the Government's consultation on planning's possible approach to HMOs, commented that the exercise had focused too heavily on student HMOs (DCLG, 2010b). At national and local levels, concentrations, howsoever defined, of student HMOs and students are implicitly and explicitly problematised. The responsibility, though, for many of the social and environmental harms that planning attributes to student occupiers arguably lies elsewhere; for example, with the landlords who fail to maintain their HMOs. The pointed language used to describe student populations in planning, with terms like "excessive" and "harmful" concentrations, "saturated areas" and "tipping points" employed, coupled with the various overt efforts to "manage" and contain student households, appear unique in today's planning system, a point alluded to by Hubbard (2008).

Discussion: "Planning as Social Control"
Viewing the study's findings through the lens of Yiftachel's (1998Yiftachel's ( , 2000 framework, it appears that by limiting the supply of HMOs, planning disproportionately affects and "controls," in particular, young adults on lower incomes. Control is expressed through all four of the framework's dimensionsterritorial, procedural, socio-economic and cultural.
In the territorial dimension, the creation of a use class covering HMOs, plus the introduction by multiple planning authorities of Article 4 Directions on HMO conversions, and of restrictive planning policies on these conversions, serve to tightly control the presence of HMOs within a community. In various municipalities, anything more than 10% of dwellings in HMO use is framed as a problem. For local planning policy, a balanced community is one in which HMOs and their occupants are in the minority. Since young, low-income adults are the typical occupants of shared houses, HMO legislation and policy, and the practices involved in its implementation, especially the use of Council Tax data on full-time student and benefit claimant status, control space through measures that would seem to exclude on the basis of income, often a proxy for social class, and age.
In the procedural dimension, residents and residents' groups have been important in shaping planning's approach to HMOs (Smith, 2008). Lobbying from residents on the perceived problems associated with high concentrations of HMOs was a key prompt for the Government's decision to commission an evidence review into the impacts of HMOs and planning's possible responses to these properties (ECOTEC, 2008). For several communities studied, a residents' petition and/or residents' representations about HMOs, prompted the planning authority to review the scale and local impacts of HMOs, and to assess whether a targeted planning response was required. A report by the National HMO Lobby (2008), a broad collective of residents' groups, seems to have been influential in informing local planning authorities' approaches to HMOs. It helped popularise the notion of a "tipping point" in respect of HMO numbers. Almost 40% of the areas with a Direction had employed, in either draft or adopted policy, the 10% tipping point conceit (expressed as a "threshold") favoured by the Lobby. Student HMOs have been a particular concern for the HMO Lobby and a similar focus is evident in the development and implementation of planning's approach to HMOs, at national and local levels.
The interests of HMO residents and advocates/supporters have been considered in the course of formulating planning's approach to HMOs. For example, planning authorities discuss in reports and background documents the potential for those groups who commonly occupy HMOs to be disproportionately affected by restrictive approaches to HMO conversions. However, the perceived advantages of a restrictive approach, including the perceived advantages for HMO residents, are presented as outweighing the disadvantages. Further, the actors favouring a restrictive approach have been notably visible in planning arenas. The number of consultees supporting more restrictive measures has tended, for example, to dwarf the number favouring more relaxed measures in national and local consultations (e.g. see DCLG, 2010b), although not always. For example, in Tower Hamlets all six respondents to the public consultation on the introduction of a borough-wide Direction opposed the measure, yet a Direction was implemented (Tower Hamlets Borough Council, 2020). Consultees' comments and objections were considered and addressed in a report to the local authority's Cabinet. For instance, in responding to opposition to the borough-wide remit of the Direction, the report noted that HMOs are dispersed across the borough and a spatially targeted approach could result in new HMO concentrations emerging. The report concluded that, although the issues raised reflected "valid considerations," and although there was the potential for adverse effects on the "financial capital" of HMO providers, there would be "greater benefits for the local community and HMO occupiers' from the introduction of a Direction (Tower Hamlets Borough Council, 2020, para. 3.22).
Regarding the socio-economic dimension of planning control, the planning legislation and policy explored within this article will restrict the availability of the kind of small, shared houses typically occupied by young, low-income adults in areas where larger numbers of these properties currently exist. This may push some individuals to different parts of the city, disconnecting them from the places and communities that orientate their lives, such as workplaces and universities. Restricting the supply of small HMOs in popular areas could also drive up rents. Those unable to afford higher rents may move to more affordable areas and/or more affordable accommodation, which might be of lower quality and/or more crowded. This may result in greater socio-spatial polarisation along income/class lines. Homeowners in areas where HMOs are tightly controlled, however, might benefit from better residential amenity, whereas HMO landlords in these areas might be able to set higher rents and benefit from an appreciating asset. Anecdotal evidence on the effects on landlords suggests this is the case (Bingham, 2018). The analysed planning legislation and policy would seem to pass on new costs to young, lowincome adults and new benefits to homeowners and private landlords, helping to perpetuate, if not magnify, existing socio-economic and intergenerational inequalities (Fainstein, 1996;Harvey, 1973).
Finally, in the cultural dimension, restrictive planning policies that limit the number of small HMOs within an area help ensure that HMO residents remain a (small) minority within a community. This has implications for the accumulation and exercise of power by HMO occupants, and the development of "alternative" cultures and identities centred on HMO residents. Policies that seek to distribute HMOs in small numbers across a city ensure that the voter power of HMO residents is spatially diluted, potentially resulting in the marginalisation of residents' interests. It might also frustrate HMO residents' efforts at local political organisation. Scattering a group across a city makes the identification of, and organisation around, common interests challenging. The mechanisms that planning authorities could employ to determine the presence of HMOs could intensify the challenge. A research paper produced by Redbridge Borough Council (2018) to inform policy options on HMOs used surname analysis of Electoral Roll and Council Tax data, picking out properties where six or more different surnames were present, as a means for determining the geography of HMOs. If this technique was used to help implement a threshold policy on HMO conversions it might result in new HMOs being less likely in areas where HMO residents are more politically engaged, insofar as they are registered to vote. This might limit the scope for HMO residents to establish larger communities of shared interest in more politically engaged areas.
Policies that seek to re-distribute HMO households across a city may impede the manifestation of "alternative" cultures and identities associated with those households (Brookfield, 2019). In respect of student HMOs, this seems to be planning's intent. There is clear resistance to neighbourhoods becoming "studentified areas," an outcome which, for some planning authorities, is seen to occur when student households are present in anything more than very small numbers. Matching Finkler and Grant's (2011) findings on planning's "assimilation aim" for disabled group-home residents, the aim appears to be for student households to be absorbed into the wider community rather than form their own communities within which student identities flourish. The promotion of relatively narrow sociocultural norms is evident in planning's approach to HMOs, whether occupied by students or other groups. As others have argued (see Ellis & McWhirter, 2008;Frisch, 2002), settled families are the desired norm in planning with the preference for this household type sometimes made explicit. For example, in Newham, an argument in favour of the introduction of a Direction was that it would "encourage people (particularly families) to remain in the borough" [emphasis added] (Newham Borough Council, 2013, p. 28). This norm is promoted via efforts to protect family housing for family use from HMO conversion, encourage students out of "family sized properties" through support for purpose-built student accommodation (Haringey Borough Council, 2017, p. 33), planning's silence on the possibility that areas could ever feature an over concentration of families and/or family housing, and the ongoing tendency to problematise single adults sharing a home.

Conclusions
Analysis of an aspect of English planning legislation, and linked local planning policy on HMOs, has broadened our understanding of planning's ability to disadvantage, exclude, control and/or oppress certain groups. The analysis provided evidence of the potential for planning to disproportionately affect young adults on lower incomes, the typical occupants of these properties, and other low-income groups, from migrants to families, who find accommodation in the shared housing sector. Evidence indicates that control is exercised over HMO residents in the four dimensions of planning controlterritorial, procedural, socioeconomic and culturalproposed by Yiftachel (1998Yiftachel ( , 2000. By tightly controlling the presence of HMOs within an area, often across an entire city, the housing options of these lower-income groups are spatially constrained in ways not experienced by other populations. This territorial control might result in higher housing costs and restricted opportunities for group members to foster alternative identities and cultures. Additionally, it may constrain opportunities for HMO residents to organise politically, resulting in the potential marginalisation of residents' interests in policy arenas. The broad similarities in approach observed across multiple local authorities suggests that a shared "rationality" in respect of HMOs exists, which 'permits only a limited range of viable, that is "politically acceptable," planning responses'namely the introduction of an Article 4 Direction on HMO conversions (Allmendinger & Gunder, 2005, pp. 104-105). This commonality of approach, combined with, at the national level, the "legislative gymnastics" undertaken to facilitate the targeted control of small shared houses, might point towards a "systematic and procedural prejudice" (Allmendinger & Gunder, 2005, p. 105) against HMOs in planning, which disproportionately affects the lower-income groups they typically house.
Employing Yiftachel's (1998) conceptual framework produced a nuanced understanding of the potential impacts of planning's approach to the regulation of small shared houses. Effects across multiple domains and spatial scales, from individuals to cities, were identified. There is clear potential to use the framework to investigate the effects of other planning measures on minorities. As a minimum, it highlights processes, policy areas and issues where inequality, disadvantage and oppression can occur, and so should be of concern to all those interested in producing better and more equitable planning outcomes. It could be used to assess existing planning policy and help inform the development of new policy. The framework also moved analysis beyond a descriptive account of a single example of planning's negative effects. Allmendinger and Gunder (2005) have argued that many studies on planning's dark side are restricted to just this objective and afford few theoretical insights.
Planning's approach to HMOs in England appeared to distort and manipulate progressive and/or prima facie neutral sentiments to facilitate measures that control and exclude less powerful groups. Previous studies have presented similar evidence of such distortion and manipulation in planning (see Finkler & Grant, 2011;Ellis & McWhirter 2008;Maldonado, 2017;Yiftachel, 1998Yiftachel, , 2000. Apparently progressive ideals, especially the wish to create and maintain balanced communities, often appeared to underpin HMO policies. For planning, anything more than a small minority of HMOs in an area was assumed to destabilise the preferred social order, tipping a community into a dangerous unbalanced state, and a sea of social, economic and environmental troubles. A concern for social balance has a long and varied history in British planning, housing and urban policy. For Cole and Goodchild (2000, p. 358), echoing Yiftachel, when this concern takes the form, as it does in the approach to HMO residents, of an interest in including "socially desirable' groups and excluding "less desirable" groups, it is 'inextricably' linked to "social control" and the active management of individuals and behaviours.
For planning, it seemed that only non-HMO residents were thought capable of forming a community, with HMO residents placed outside, and viewed as a potential threat to, the community. It appeared that HMO residents were understood as different, as "other" (Jensen, 2011). Planners, and those residents who lobbied against HMOs, seemed particularly disposed to othering student HMO residents. These individuals may, though, have been students themselves and may have deep connections to the student population through friends or adult children. Unusually, then, planners and residents were, in a way, othering past versions of the self and individuals whose lives may be deeply entwined with their own. They were not othering some distant outsider (Jensen, 2011). For residents and for planning, the distinctions and social distance between "us" and "them," between the "self" and the "other," appear finely and tightly drawn, although residents and planners would likely disagree. Previous research has, for example, found that long-term residents view students as deviating from the social norms and behaviours which they themselves practice and favour (Brookfield, 2019;Sage et al., 2012a). However, given the typical demographic traits of the planning profession (Rahder & Milgrom, 2004), the residents who usually participate in planning (Brand & Gaffikin, 2007;Brookfield, 2017) and university students (Reay et al., 2010), on dimensions such as class and ethnicity students are likely to resemble planners and planning-engaged residents. Further, one might expect areas of overlap in each actor's variety of probably middle-class habitus (Hillier & Rooksby, 2016). By othering, targeting and restricting a group which may share numerous characteristics with the insider group, planning appears to promote within built environments narrow and exclusionary understandings of what is "in place" and "out of place" (Cresswell, 1996) that 'limit respect for identity and difference' (Layard, 2012, p. 575), homogenise space (Rahder & Milgrom, 2004;Yiftachel, 1998), and prioritise and secure the interests of established residents. Note 1. Although not the focus of this article, the requirement under the Housing Act 2004 for HMOs containing five or more residents to be licensed by a local authority, and the need for HMOs housing seven or more residents to have planning permission, provide further mechanisms via which municipal authorities control the provision of multi-occupancy housing.