3.—(1) Where there are in a dwelling-house let on a secure tenancy one or more interests which are interests to which this article applies, and the dwelling-house is a house, Part V (the right to buy) has effect with the modifications specified in the Schedule to this Order.
(2) This article applies to an interest held by—
a local authority,
a new town corporation,
a housing action trust,
an urban development corporation,
the Development Board for Rural Wales,
the Corporation(1), or
a registered housing association, other than one excepted from the right to buy by Schedule 5, paragraph 1 (charities), 2 (co-operatives) or 3 (associations which have not received grant),
which is immediately superior to the interest of the landlord or to another interest to which this article applies.
See paragraph 107 of Schedule 17 to the Housing Act 1988 (c. 50).