“ 29 Assessment where loss of tax discovered (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 (b) . . . (c) . . . 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.”
“(1) An assessment on any person (in this section referred to as “the person in default”) for the purpose of making good to the Crown a loss of income tax or capital gains tax attributable to his fraudulent or negligent conduct or the fraudulent or negligent conduct of a person acting on his behalf may be made at any time not later than 20 years after the 31st January next following the year of assessment to which it relates.”
“(1) An assessment on a person in a case involving a loss of income tax or capital gains tax brought about carelessly by the person may be made at any time not more than 6 years after the end of the year of assessment to which it relates (subject to subsection (1A) and any other provision of the Taxes Acts allowing a longer period). (1A) An assessment on a person in a case involving a loss of income tax or capital gains tax— (a) brought about deliberately by the person, (b) attributable to a failure by the person to comply with an obligation under section 7, or (c) . . . may be made at any time not more than 20 years after the end of the year of assessment to which it relates (subject to any provision of the Taxes Acts allowing a longer period). (1B) In subsections (1) and (1A), references to a loss brought about by the person who is the subject of the assessment include a loss brought about by another person acting on behalf of that person.”
“ 10 (1) This article applies where an event specified in paragraph 4 below relates to a year of assessment in respect of which a person (“P”) has not been given notice under— (a) section 8 of TMA 1970 (personal return), (b) section 8A of TMA 1970 (trustee's return), or (c) section 12AA of TMA 1970 (partnership return), within one year of the end of the year of assessment. (2) Where this article applies, the day appointed for the coming into force of paragraphs 1 to 31 and 37 to 65 is1st April 2012 . (3) But this article does not apply if, as regards P and a year of assessment, 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 an assessment to tax has become insufficient, or any relief which has been given has become excessive. (4) The events referred to in paragraph (1) above are— (a) an assessment on P to income tax or capital gains tax, (b) a claim by or on behalf of P, provided for by any provision of the Taxes Acts, and (c) a notice given by P under section 711 of the Income Tax (Earnings and Pensions Act) 2003 (right to make a return). (5) Nothing in this article has any application where P is a company.”
“ 7 Section 36(1A)(b) and (c) of TMA 1970 (fraudulent and negligent conduct) shall not apply where the year of assessment is 2008-09 or earlier, except where the assessment on the person (“P”) is for the purposes of making good to the Crown a loss of tax attributable to P's negligent conduct or the negligent conduct of a person acting on P's behalf.”