20. Offence relating to membership of a terrorist organisation:
(1) A person commits an offence if he belongs or professes to belong to a terrorist organisation:
Provided that this sub-section shall not apply where the person charged is able to prove-
(a) That the organisation was not declared as a terrorist organisation at the time when he became a member or began to profess to be a member; and
(b) That he has not taken part in the activities of the organisation at any time during its inclusion in the Schedule as a terrorist organisation.
(2) A person guilty of an offence under this section shall be liable, on conviction, to imprisonment for a term not exceeding ten years or with fine or with both.