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.

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.

British lawmakers voted on Wednesday to ban pro-Palestinian campaign group Palestine Action as a terrorist organisation, after its activists broke into a military base and damaged two planes in protest at what it says is Britain's support for Israel.