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HMRC internal manual

Employment Income Manual

Assessments, appeals and other procedures: discovery assessments

Section 29 TMA 1970

Sometimes it may be necessary to make an assessment after a self assessment has already been made and:

  • the self assessment has already been enquired into and the enquiry has been closed, or
  • the time limit for enquiring into a self assessment has expired.

In these circumstances any action can only be taken under Section 29 TMA 1970. EM3250 onwards in the Enquiry Manual and the Self Assessment Manual cover the making of discovery assessments.

A discovery assessment may be needed where, for example, employment income was omitted from a self assessment or where in a self assessment a taxpayer claimed a PAYE credit because of an employer PAYE failure, but subsequently a direction is made under the PAYE regulations to collect the tax from the employee, see the Compliance Operational Guidance (COG) manual at COG915175 onwards for further information about directions.