The ACT available for set-off against a company's liability for an accounting period is the total of any ACT:
The amount of the set-off is limited to an amount equal to the
ACT that would have been payable in respect of a distribution made
at the end of the period of an amount which, together with the ACT
thereon, is equal to the company's CT profit for the accounting
period.
Guidance on the regime for accounting periods ending before 6
April 1999 can be found at
CTM20000 onwards.