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HMRC internal manual

VAT Assessments and Error Correction

Powers of assessment: VAT assessment powers: How to work out the four and two year span

The four year span (other than long first period returns)

This is calculated from the last day of the prescribed accounting period for which the assessment is to be made. The assessment must be both made and notified no later than four years from that day, or you will be out of time.

For officer’s assessments, the four year span does not run from the date on which the return is due (i.e. due date). There is no extra month’s grace allowed for officers assessments.

When reckoning the four year span, it is the last day of the quarterly or monthly accounting period which is relevant. So if part of the accounting period covered by your assessment is over four years old, you can still assess providing the last day of the period is no older than four years on the day you make the assessment.


Business is on VAT accounting periods that end January/April/July/ October. On an assurance visit dated 31 August 2010 the officer discovers that the business has under-declared output tax on a number of invoices proper to period 10/06 and wishes to make an assessment.

To be in time under the four year rule the assessment must be made by 31 October 2010.

The two year span (other than long first period returns)

You can work out the two year span in exactly the same way as the four year span, but replace references to ‘four years’ with ‘two years’. In the above example an assessment is already out of time under the two year rule before the officer’s visit as it had to be made by 31s t October 2008.