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HMRC internal manual

Oil Taxation Manual

Non-residents working on the UK continental shelf: self assessment and appeals: discovery assessments and appeals


HMRC may make a discovery assessment to make good a loss of tax where it is discovered that:

  • an amount which ought to have been assessed to tax has not been assessed, or
  • an assessment to tax is or has become insufficient

provided a company tax return has been delivered where there has been fraudulent or negligent conduct on the part of the company or a person acting on the company’s behalf (see FA98\Sch18\paras41 & 43).


An appeal may be brought against a discovery assessment provided it is made in writing and sent to HMRC within 30 days after the notice of assessment is issued - FA1998\Sch18\para 48.

From 1st April 2009 the Tribunal procedure will apply. A review may be requested and an appeal should be made to the First Tier Tribunal.