11(1)A person is an exempt individual on a particular day if at any time on the day he has his sole or main residence in a building which on the day concerned is designated under this paragraph.
(2)The Secretary of State may designate a building under this paragraph if at the time of designation the first and second conditions are fulfilled.
(3)The first condition is that—
(a)the Crown has a freehold interest in the whole building and it is not subject (as a whole) to a single leasehold interest, or
(b)the Crown has an interest in the whole building under a lease or underlease and it is not subject (as a whole) to a single inferior leasehold interest.
(4)The second condition is that in the Secretary of State’s opinion the building is used wholly or mainly as the sole or main residence of individuals, and in his opinion most or all of them—
(a)reside there for short periods, or
(b)should in the interests of national security not be registered as subject to a personal community charge.
(5)The Secretary of State shall revoke a designation under this paragraph if the first or second condition ceases to be fulfilled.
(6)A designation under this paragraph shall take effect at the beginning of the day following that on which it is made, and shall cease to have effect at the end of the day (if any) on which it is revoked.
(7)The Crown has an interest in a building if the interest belongs to Her Majesty in right of the Crown or of the Duchy of Lancaster, or belongs to the Duchy of Cornwall or a government department, or is held for the purposes of a government department.