664. Evidence in cases of fraudulent conduct.

Statements made or documents produced by or on behalf of a person are not inadmissible in:


    (1)     any criminal proceedings against the person in question for any form of fraudulent conduct in connection with or in relation to tax;


    (2)     any proceedings against him for the recovery of any tax due from him; and


    (3)     any proceedings for a penalty or on appeal against the determination of a penalty,

by reason only that it has been drawn to his attention that:


    (a)     where serious tax fraud has been committed the Commissioners for HM Revenue and Customs may accept a money