This paper uses data produced by the Ministry of Justice to look for trends in the numbers of various categories of patients detained under the Mental Health Act in England and Wales between 2003 and 2016. Specifically, we have focussed on patients detained with Ministry of Justice restrictions in place. The number of ‘restricted’ patients, who are largely detained in secure psychiatric hospitals, has risen substantially during this period. If this trend continues, there will be the need for further expansion of secure psychiatric beds in the years ahead. Factors driving the increased number of restricted patients are discussed in this paper.