(1)If a person carrying on a trade has on or after the relevant date incurred expenditure in taking, in respect of any premises used by him for the purposes of the trade—
(a)steps specified, in a letter or other document sent or given to him by or on behalf of the fire authority on an application for a fire certificate under the [1971 c. 40.] Fire Precautions Act 1971 in respect of those premises, as steps that would have to be taken in order to satisfy the authority as mentioned in subsection (4) of section 5 of that Act, being steps that might have been, but were not, specified in a notice under that subsection; or
(b)steps which, in consequence of the making of an order under section 10 of that Act prohibiting or restricting the use of the premises, had to be taken to enable the premises to be used without contravention of the order,
then, if an allowance or deduction in respect of the expenditure could not, apart from this section, be made in taxing the trade or computing the profits or gains arising from it, Chapter I of Part III of the [1971 c. 68.] Finance Act 1971 shall apply as regards the expenditure as it would apply by virtue of section 17 of the [1974 c. 30.] Finance Act 1974 if the expenditure fell within the said section 17.
(2)For the purposes of this section the relevant date, in relation to expenditure incurred in taking steps falling within subsection (1)(a) above, is 1st June 1972 and, in relation to expenditure incurred in taking steps falling within subsection (1)(b) above, is 20th March 1972.
(3)This section shall be construed as if contained in Chapter I of Part III of the Finance Act 1971.