78.—(1) In any proceedings before the Court (including an appeal) which involve or relate to—

( a ) the revocation of the registration of a trade mark, or

( b ) a declaration of the invalidity of the registration of a trade mark, or

( c ) the rectification of the register, or

( d ) any other matter in which the relief sought would affect the register,

the Controller shall be entitled to appear and be heard, and shall appear if so directed by the Court.

(2) Unless otherwise directed by the Court, in any proceedings before the Court the Controller may instead of appearing submit to the Court a statement in writing signed by the Controller, giving particulars of—

( a ) any proceedings before the Controller in relation to the matter in issue;

( b ) the grounds of any decision given by the Controller affecting it;

( c ) the practice of the Patents Office in like cases; or

( d ) such matters relevant to the issues and within the Controller's knowledge as the Controller thinks fit;

and the statement shall be deemed to form part of the evidence in the proceedings.