More than 20 people have been arrested during a protest in London in support of Palestine Action, a group which has been banned under UK anti-terrorism laws.

Pro-Palestinian campaign group Palestine Action's co-founder on Friday lost a bid to pause the British government's decision to ban the group under anti-terrorism laws, with the group losing an urgent appeal meaning it will be banned from midnight.

An 83-year-old retired priest has been arrested in Britain for defying a controversial new ban on the activist group Palestine Action, sparking widespread outrage over what critics call a severe blow to freedom of expression.