Housing Act 1985

3 (1) The limit is that the aggregate of that amount and the amount for the time being secured by the mortgage shall not exceed—

(a) where the right to a further advance belongs to one person, the amount to be taken into account, in accordance with regulations under paragraph 4, as his available annual income multiplied by such factor as, under the regulations, is appropriate to it;

(b) where the right to a further advance belongs to more than one person, the aggregate of the amounts to be taken into account in accordance with the regulations as the available annual income of each of them, after multiplying each of those amounts by the factor appropriate to it under the regulations.

(2) Where the amount which a tenant is entitled to have advanced to him is reduced by the limit imposed by this paragraph, the landlord may, if it thinks fit and the tenant agrees, treat him as entitled to have advanced to him such amount exceeding that limit, but not exceeding the amount of his additional contribution, as the landlord may determine.