(1)A local housing authority’s local contribution differential for a year of account is the amount by which their reckonable income for that year exceeds their reckonable income for the preceding year (and accordingly is nil or, as the case may be, a negative amount if their reckonable income for the year is the same as or less than that for the preceding year).
(2)An authority’s reckonable income for a year is the amount which, in accordance with any determination made by the Secretary of State, the authority are assumed to receive for that year as income which they are required to carry to their Housing Revenue Account including—
(a)any contribution made by the authority out of their general rate fund, and
(b)any rent rebate subsidy payable under section 32 of the [1982 c. 24.] Social Security and Housing Benefit Act 1982,
but excluding any other subsidy, grant or contribution.
(3)A determination shall state the assumptions on which it is based and the method of calculation used in it, and in making it the Secretary of State shall have regard, amongst other things, to past and expected movements in incomes, costs and prices.
(4)A determination may be made for all local housing authorities or different determinations may be made—
(a)for authorities of different descriptions, or
(b)for authorities in England and authorities in Wales, or in different parts of England and Wales, or
(c)for individual authorities.
(5)Before making a determination for all local housing authorities the Secretary of State shall consult organisations appearing to him to be representative of local housing authorities.
(6)A determination shall be made known to the authorities for which it is made in the year preceding the year of account for which it is to have effect.