(1)Where a person becomes liable to a penalty under this Chapter, WRA must—
(a)assess the penalty,
(b)issue a notice to the person of the penalty assessed, and
(c)state in the notice the period or transaction in relation to which the penalty has been assessed.
(2)An assessment of a penalty under this Chapter may be combined with an assessment to devolved tax.
(3)An assessment of a penalty under section 129 or 132 must be made before the end of the period of 12 months beginning with—
(a)the end of the appeal period for the decision correcting the inaccuracy, or
(b)if there is no assessment to the tax concerned as a result of that decision, the day on which the inaccuracy is corrected.
(4)An assessment of a penalty under section 133 must be made before the end of the period of 12 months beginning with—
(a)the end of the appeal period for the assessment of tax which corrected the understatement, or
(b)if there is no assessment correcting the understatement, the day on which the understatement is corrected.
(5)In subsections (3) and (4), “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.
(6)Subject to subsections (3) and (4), a supplementary assessment may be made in respect of a penalty under this Chapter if an earlier assessment operated by reference to an underestimate of the potential lost revenue.