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HMRC internal manual

Enquiry Manual

Reopening Earlier Years: Discovery in SA Years: Obvious Errors

If you spot an obvious error in a return - for example an arithmetical error - of a kind that could have been corrected, but the time limits for repair/correction under that section and for Section 9A/Para 24 have expired, you will have to consider the discovery provisions.

It is unlikely that you will be able to make an assessment under Section 29(5) since, if the error was `obvious’, the information to identify it would have been `made available’ to you. You would therefore have to rely on Section 29(4) and argue that the error was attributable to the careless behaviour of the taxpayer or agent. If the error was obvious and there was no concealment it would be less serious than if it were concealed.