In section 4(1) of the [1968 c. 13.] National Loans Act 1968 (which provides that the aggregate of any commitments of the Public Works Loan Commissioners in respect of undertakings to grant local loans and any amount outstanding in respect of the principal of such loans shall not exceed £42,000 million or such other sum not exceeding £50,000 million as the Treasury may specify by order) for the words “£42,000 million” and “£50,000 million” there shall be substituted respectively “£55,000 million” and “£70,000 million”.