Cleverly has power to proscribe an organsation under British law if the group is believed to be "concerned in terrorism, and it is proportionate to do" according to the government's website.

Proscription means that it will be a criminal offence in Britain to belong to or promote the group, arrange its meetings, and carry its logo in public.

Those breaching the rules could face up to 14 years in jail.

(Reporting by Sachin Ravikumar; editing by William James)