If a person carrying on a trade enters the cash basis for a tax year, any cash basis deductible amount may not be carried forward as unrelieved qualifying expenditure in the pool for the trade from the chargeable period ending F2in the previous tax year (or, if there is more than one such period, the latest of them).

A “cash basis deductible amount” means any amount of unrelieved qualifying expenditure for which a deduction would be allowed in calculating the profits of the trade on the cash basis on the assumption that the expenditure was paid in the tax year for which the person enters the cash basis.

Any cash basis deductible amount is to be determined on such basis as is just and reasonable in all the circumstances.

Subsections (9) and (11) of section 1A (capital allowances and charges: cash basis) apply for the purposes of this section as they apply for the purposes of that section.