In the United Kingdom, the value of civil defence remains controversial. Proponents of civil defence argue that it is a necessary humanitarian duty to mitigate the impact of potential future war on the civilian population. Opponents point to ministerial and military statements that the principal function of civil defence is to enhance the credibility of nuclear deterrence, not to protect people.

Against a backdrop of this broad debate, the issue of civil preparedness for possible chemical or biological attack is examined. This article considers current expert advice delivered to local authority emergency planning officers and volunteer civil defence Scientific Advisers at a Seminar held in May 1987, in the context of developments in chemical and biological weaponry and UK government policy. Detailed consideration is given to the difficulties in executing suggested individual and collective protection measures, and it is argued that a ‘credibility gap’ exists between advice on protection and the capacity for its effective implementation.