19In section 20 (4) (b) of the Rent Act 1957, the reference to the local authority shall, in the case of houses the construction of which was promoted either by the London county council or by the Greater London Council or in respect of which improvement grants were made by either of those councils under the Housing Act 1949 or the Housing (Financial Provisions) Act 1958, be construed as a reference to the Greater London Council.