Thousands of people gathered on Saturday in London urging British lawmakers to object to the UK’s plan of possibly launching air strikes on DAESH terrorist group in Syria.
The British parliament is scheduled to vote on the matter next week after Prime Minister David Cameron pushed the MPs to support the move in the wake of Paris terror attacks.
The protesters were chanting "Don't bomb Syria" as they gathered outside Cameron's 10 Downing St. office.
The Stop The War Coalition movement had organised this demonstration along with other ones that were held in other cities across the country on the same day.
"The proposed vote in parliament on bombing Syria by British forces is likely to take place within the next week," Stop The War Coalition said in a statement, adding that "yet this bombing will not stop terror attacks."
Actor Mark Rylance and musician Brian Eno will also be giving a letter to Downing Street urging Cameron not to join the international air strikes against the terrorist organisation in Syria.
Britain's Royal Air Force is already part of a US-led air campaign against DAESH in Iraq, and on Thursday Cameron argued that the strikes should be extended to Syria.
"We have to hit these terrorists in their heartlands," he emphasised.
The current opposition Labour Party leader Jeremy Corbyn, who also assisted in the setting up of the Stop The War Coalition, is facing deep divisions in his party regarding the looming vote.
Corbyn is standing against the air strikes in Syria while many of his MPs are in favour of such an extension.