Taxes Management Act 1970 section 43A

Further assessments: claims etc.

Section 43A provides taxpayers with the ability to make, revoke or vary claims, elections and notices when HMRC raises a discovery assessment under section 29, provided the assessment was not made to recover tax lost through careless or deliberate behaviour.

• When HMRC makes a discovery assessment for income tax or capital gains tax that is not related to careless or deliberate loss of tax, the taxpayer may make new claims, elections or notices — or revoke or vary existing ones — within one year from the end of the tax year in which the assessment is made
• Certain elections are excluded from this provision, notably elections to transfer married couple's or civil partner's allowances and elections for capital gains tax rebasing of assets to 31 March 1982
• A claim, election or notice is considered relevant if it relates to the year of assessment in question and has, or could have, the effect of reducing the increased tax liability arising from the assessment or other tax liabilities for that year or the following year (ending no later than one year after the end of the year of assessment in which the assessment was made)
• Where a claim, election or notice is made, revoked or varied under this section, HMRC must make all necessary adjustments — including repayments of tax or further assessments — to reflect the effect on any person's tax liability, and normal appeal rights apply to any decisions on revocations or variations