A5.309 Judicial review—proceedings under Civil Procedure Rules, Parts 7 and 8
Probably the most common type of revenue proceedings are enforcement proceedings, where HMRC seek to collect tax that has become due. These proceedings, like most debt proceedings, are commenced using a normal Civil Procedure Rules (CPR), Pt 7 claim form.
In IRC v Aken1, the Court of Appeal considered the extent to which it was open to a taxpayer to argue that he was not liable to pay tax as a defence to enforcement proceedings. The court considered that it was implicit from TMA 1970, s 46(2) that issues that have been determined by the Commissioners or settled by a TMA 1970, s 54 agreement cannot be raised as a defence to enforcement proceedings. The court considered that the validity of the assessment could not be challenged in such proceedings. The court observed2 that the fact that an assessment is excessive or even was made on an incorrect view of the law does not make it invalid. These issues therefore cannot be raised as a defence in enforcement proceedings, they instead must be raised on appeal3.
However, it is considered that there is no reason why the court should not have jurisdiction to consider the validity of an assessment or other procedural steps in enforcement proceedings in cases where the errors are jurisdictional. In Lord Advocate v Shanks4 the Court of Session considered that the fact that a VAT assessment was out of time could be raised as a defence to