A Palestine Action protest is under way in central London ahead of an expected government announcement on proscribing the group as a terrorist organisation.
Hundreds of people met at Trafalgar Square after police banned them from protesting outside of Parliament.
Activists from the group broke into RAF Brize Norton in Oxfordshire last week and spray-painted military planes red to protest against the UK’s support of Israel during the war in Gaza.
Metropolitan Police chief Sir Mark Rowley said he was “shocked and frustrated” about the protest, but said it could not be stopped unless proscription came into force.
Scuffles have broken out at the protest, with at least two people arrested.
Organisers made the last-minute venue change after Scotland Yard enforced an exclusion zone across much of Westminster.
Met Commissioner Sir Mark said while the force had no legal power to stop the protest, they would impose the conditions “robustly”.
Charing Cross, next to Trafalgar Square, was blocked for a time as the protesters gathered.
Some supporters of the group waved Palestinian flags and carried placards, with other protesters chanting: “We will not be silenced.”
Home Secretary Yvette Cooper is expected to announce plans to proscribe Palestine Action on Monday afternoon, effectively branding it a terrorist organisation.
It is understood this would start a parliamentary process which means Palestine Action would not be immediately proscribed, even once the statement is made.
The expected move to proscribe the group has drawn criticism from a number of human rights groups and activists.
Labour peer and activist Baroness and Shami Chakrabarti said that she did not advocate criminal activity in protest, she felt proscription was a “step too far.”
Chancellor Rachel Reeves condemned Palestine Action’s behaviour as “totally unacceptable” ahead of the statement in Parliament later.
“To cause damage to military assets, but also to cause such damage to privately owned assets, it is unacceptable whatever your views are on what’s happening in the Middle East,” she said.
