(1)An assessment of a penalty under this Chapter in respect of any amount must be made on or before the later of date A and (where it applies) date B.
(2)Date A is the last day of the period of 2 years beginning with—
(a)in the case of failure to make a tax return, the filing date, or
(b)in the case of failure to pay a devolved tax, the penalty date.
(3)Date B is the last day of the period of 12 months beginning with—
(a)in the case of a failure to make a tax return—
(i)the end of the appeal period for the assessment of the amount of devolved tax to which a person would have been liable if the tax return had been made, or
(ii)if there is no such assessment, the date on which that liability is ascertained or it is ascertained that the liability is nil;
(b)in the case of a failure to pay a devolved tax—
(i)the end of the appeal period for the assessment of the amount of devolved tax in respect of which the penalty is assessed, or
(ii)if there is no such assessment, the date on which that amount of devolved tax is ascertained.
(4)In subsection (2)(b), “penalty date” has the meaning given by section 122(2).
(5)In subsection (3)(a) and (b), “appeal period” means the later of the following periods—
(a)if no appeal is made, the period during which an appeal could be made, and
(b)if an appeal is made, the period ending with its final determination or withdrawal.