1A

In the case of an obligation under section 7 of TMA 1970 which arises by virtue of subsection (1B) of that section, the potential lost revenue is so much of any income tax or capital gains tax to which P is liable in respect of the tax year in question as is, by reason of the failure to comply with the obligation—

a

where the period specified in subsection (1C)(b)(ii) of that section applies and ends after the relevant date, unpaid at the end of that period, or

b

in any other case, unpaid on the relevant date.

1B

For the purposes of sub-paragraph (1A) the relevant date is—

a

31 January following the tax year, or

b

if, after that date, HMRC refund a payment on account in respect of the tax year to P, the day after the refund is issued.