The protest group was officially classified as a terrorist organisation from midnight on Saturday after the measure received overwhelming support from MPs and following the failure of a last-minute legal challenge to delay it.

The decision means that the group called Palestine Action will be banned as a terrorist organization in Britain while its full legal challenge to the ban plays out.

British police on Saturday arrested more than 20 people on suspicion of terrorism offences after they demonstrated beneath a statue of Mahatma Gandhi in London in support of the Palestine Action group.