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).
An assessment on a person in a case involving a loss of income tax or capital gains tax —
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).
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.
Where the person mentioned in subsection (1) or (1A) ("the person in default") carried on a trade, profession or business with one or more other persons at any time in the period for which the assessment is made, an assessment in respect of the profits or gains of the trade, profession or business in a case mentioned in subsection (1A) or (1B) may be made not only on the person in default but also on his partner or any of his partners.
If the person on whom the assessment is made so requires, in determining the amount of the tax to be charged for any chargeable period in any assessment made in a case mentioned in subsection (1) or (1A) above, effect shall be given to any relief or allowance to which he would have been entitled for that chargeable period on a claim or application made within the time allowed by the Taxes Acts.
In subsection (3) above, "claim or application" does not include an election under ... any of sections 47 to 49 of ITA 2007 (tax reductions for married couples and civil partners: elections to transfer relief) ... .
Any act or omission such as is mentioned in section 98B below on the part of a grouping (as defined in that section) or member of a grouping shall be deemed for the purposes of subsections (1) and (1A) above to be the act or omission of each member of the grouping.