NHS England must arrange for the provision of hospital accommodation and services for persons who—
are liable to be detained under the Mental Health Act 1983 (c. 20), and
in the opinion of the Secretary of State require treatment under conditions of high security on account of their dangerous, violent or criminal propensities.
The hospital accommodation and services mentioned in subsection (1) are referred to in this section and paragraph 15 of Schedule 4 (NHS trusts) as "high security psychiatric services".
High security psychiatric services may be provided —
only at hospital premises at which services are provided only for the persons mentioned in subsection (1), and
only by a person approved by the Secretary of State for the purposes of this subsection.
The Secretary of State may—
give directions to a person who provides high security psychiatric services about the provision by that person of those services;
give directions to NHS England about the exercise of its functions in relation to high security psychiatric services.
"Hospital premises" means—
a hospital, or
any part of a hospital which is treated as a separate unit.