(1)The Treasury shall ensure that the aggregate of outstanding expenditure under section 16(1)(b) and (c) does not at any time exceed £400 million.
(2)For the purpose of subsection (1)—
(a)outstanding expenditure in respect of the acquisition of assets, securities and rights shall be taken to be the aggregate of amounts paid for the acquisition of assets, securities and rights which have not been disposed of,
(b)outstanding expenditure in respect of a loan shall be taken to be the amount outstanding in respect of the principal,
(c)outstanding expenditure in respect of a guarantee shall be taken to be the aggregate of amounts which have been paid in fulfilment of it and in respect of which the Treasury have not been reimbursed, and
(d)the Treasury shall make arrangements for evaluating outstanding expenditure in respect of anything done under section 16(1)(b) or (c) which is not addressed by paragraphs (a) to (c) above.
(3)The Treasury may by order substitute a new amount for the amount for the time being specified in subsection (1).
(4)An order under subsection (3)—
(a)shall be made by statutory instrument, and
(b)shall not be made unless a draft has been laid before, and approved by resolution of, each House of Parliament.