“29(1) If an officer of the Board or the Board discover, as regards any person (the taxpayer) and a year of assessment— (a) that any income which ought to have been assessed to income tax, or chargeable gains which ought to have been assessed to capital gains tax, have not been assessed, or … the officer or, as the case may be, the Board may, subject to subsections (2) and (3) below, make an assessment in the amount, or the further amount, which ought in his or their opinion to be charged in order to make good to the Crown the loss of tax.”
“(3) The amendments made by this section— (a) have effect in relation to the tax year 2021-22 and subsequent tax years, and (b) also have effect in relation to the tax year 2020-21 and earlier tax years but only if the discovery assessment is a relevant protected assessment (see subsections (4) to (6)). (4) A discovery assessment is a relevant protected assessment if it is in respect of an amount of tax chargeable under— (a) Chapter 8 of Part 10 of ITEPA 2003 (high income child benefit charge), … (5) But a discovery assessment is not a relevant protected assessment if it is subject to an appeal notice of which was given to HMRC on or before30 June 2021 where— (a) an issue in the appeal is that the assessment is invalid as a result of its not relating to the discovery of income which ought to have been assessed to income tax but which had not been so assessed, and (b) the issue was raised on or before30 June 2021 (whether by the appellant or in a decision given by the tribunal). (6) In addition, a discovery assessment is not a relevant protected assessment if— (a) it is subject to an appeal notice of which was given to HMRC on or before30 June 2021 , (b) the appeal is subject to a temporary pause which occurred before27 October 2021 , and (c) it is reasonable to conclude that the temporary pausing of the appeal occurred (wholly or partly) on the basis that an issue of a kind mentioned in subsection (5)(a) is, or might be, relevant to the determination of the appeal. (7) For the purposes of this section the cases where notice of an appeal was given to HMRC on or before30 June 2021 include a case where— (a) notice of an appeal is given after that date as a result of section 49 of TMA 1970, but (b) a request in writing was made to HMRC on or before that date seeking HMRC's agreement to the notice being given after the relevant time limit (within the meaning of that section). (8) For the purposes of this section an appeal is subject to a temporary pause which occurred before27 October 2021 if— (a) the appeal has been stayed by the tribunal before that date, (b) the parties to the appeal have agreed before that date to stay the appeal, or (c) HMRC have notified the appellant (“A”) before that date that they are suspending work on the appeal pending the determination of another appeal the details of which have been notified to A.”
“34(1) Subject to the following provisions of this Act, and to any other provisions of the Taxes Acts allowing a longer period in any particular class of case, an assessment to income tax or capital gains tax may be made at any time not more than 4 years after the end of the year of assessment to which it relates. 34(2) An objection to the making of any assessment on the ground that the time limit for making it has expired shall only be made on an appeal against the assessment. …”