24(1)References to a liability to tax which would have been shown in a return are references to the amount which, if a complete and accurate return had been delivered on the filing date, would have been shown to be due or payable by the taxpayer in respect of the tax concerned for the period to which the return relates.U.K.
(2)In the case of a penalty which is assessed at a time before P makes the return to which the penalty relates—
(a)HMRC is to determine the amount mentioned in sub-paragraph (1) to the best of HMRC's information and belief, and
(b)if P subsequently makes a return, the penalty must be re-assessed by reference to the amount of tax shown to be due and payable in that return (but subject to any amendments or corrections to the return).
(3)In calculating a liability to tax which would have been shown in a return, no account is to be taken of any relief under subsection (4) of section 419 of ICTA (relief in respect of repayment etc of loan) which is deferred under subsection (4A) of that section.