(1)Detention under section 250 or 259 is to be in such place and under such conditions—
(a)as the Secretary of State may direct, or
(b)as the Secretary of State may arrange with any person.
(2)A person detained pursuant to directions or arrangements made by the Secretary of State under this section is deemed to be in legal custody.
Detention under section 254 (extended sentence of detention) is to be in a place and under conditions determined by, or by a person authorised for the purpose by, the Secretary of State.