In recent years there has been a marked increase in the proportion of individuals with mental disorders detained in hospital involuntarily, compared to those admitted on an informal basis (Wall et al, 1999). There is also growing concern about legally incompetent patients being treated under the doctrine of necessity (Eastman & Peay, 1998). The rise in the numbers of detained patients may have come about for a variety of reasons. Suggested possible contributory factors include a reduction in psychiatric hospital beds; the move towards community care and the consequent tendency to maintain patients at home for longer; increasing comorbidity and more severely disturbed behaviour on hospital wards; and a greater number of individuals transferred to hospital care from the criminal justice system (Mental Health Act Commission, 1999). Statutory mental health legislation in the UK has remained essentially unchanged, in some cases, for nearly 15 years. There have been additions and amendments during that period, as well as new law. For instance, the Mental Health (Patients in the Community) Act 1995, dealing with the care and treatment of people with mental disorders, and the Criminal Evidence (Amendment) Act 1994, covering specific issues to do with certain groups of those suffering from psychiatric disorders. Despite this there is clear evidence from recent research from various parts of the UK that medical practitioners, most particularly psychiatrists, and even those using the Mental Health Act on a day-to-day basis, do not necessarily possess a detailed knowledge of the law. Among a random sample of Section 12(2) approved medical practitioners in the West Midlands, none of those interviewed was able to define the term mental disorder as used in the Act, and only just over one-third correctly identified the four legal categories of mental illness, mental impairment, severe mental impairment and psychopathic disorder (Bhatti et al, 1999). In similar studies undertaken in Scotland, only one in 10 of a national sample of consultant psychiatrists was able to give the statutory definition of the term mental disorder (Humphreys, 1998) and among a similar non-consultant sample only 28% were able to give the correct title and year of the Mental Health (Scotland) Act 1984 (Humphreys, 1997). It would seem important, therefore, that psychiatrists do not become complacent about their knowledge and use of the Act, even though there has been considerable debate around the issue of how much expertise and precise factual knowledge of specific legislation is actually required.