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HMRC internal manual

Self Assessment Claims Manual

Appendix 1: Old Error or Mistake Relief: What it Covers

From 1 April 2010, it is not possible to make a claim for the old error or mistake relief for any period.  The relief is replaced by overpayment relief, see SACM12000+.  You will only need the guidance in SACM Appendix 1 if you are dealing with a claim made before 1 April 2010.

The expression `error or mistake’ covers

  • errors of omission such as the non-deduction of an admissible expense
  • errors of commission, such as computational or arithmetical errors
  • errors arising from a misunderstanding of the law, and
  • erroneous statements of fact.

If the taxpayer contends that they have not been given credit for an amount of tax deducted at source, it is not necessary for them to make a claim under Section 33 as they have an automatic entitlement to the tax deducted.