The Civil Procedure Rules 1998

[F1Function of a special advocateE+W

79.19.  The function of a special advocate is to represent the interests of a party other than the Treasury by, for example—

(a)making submissions to the court at any hearing from which the party and that party’s legal representative are excluded;

(b)adducing evidence and cross-examining witnesses at such a hearing;

(c)making applications to the court or seeking directions from the court where necessary; and

(d)making written submissions to the court.]