Powers of assessment: VAT assessment powers: The two year rule
This is the most fundamental assessment time limit. You can assess for a prescribed accounting period, at any time after the due date for submission of the VAT return.
However providing that the last day of the period which contains the misdeclaration, or for which no return was rendered, is no older than 2 years on the day you make and notify your assessment the two year rule will apply.
If this is the case you need not concern yourself with any other time limits.
For assessments under Section 73(2) raised on or after 19th March 2008 the 2 year rule runs from the end of the prescribed accounting period in which the VAT was paid or credited.