Crimes Against Humanity and War Crimes Act 2000
22. Every person is guilty of an indictable offence and liable to imprisonment for a term of not more than two years who, in respect of an existing or proposed proceeding of the International Criminal Court,
(a) signs a writing that purports to be an affidavit or statutory declaration and to have been sworn or declared before them when the writing was not so sworn or declared or when they know that they have no authority to administer the oath or declaration;
(b) uses or offers for use any writing purporting to be an affidavit or statutory declaration that they know was not sworn or declared, as the case may be, by the affiant or declarant or before a person authorized to administer the oath or declaration; or
(c) signs as affiant or declarant a writing that purports to be an affidavit or statutory declaration and to have been sworn or declared by them, as the case may be, when the writing was not so sworn or declared.
Giving false testimony
Presenting false or forged evidence
National penalties - maximum penalty
EDIT.