Anti-war protesters gathered outside Parliament and Labour Party headquarters this evening as the House of Commons prepares to debate whether Britain should launch airstrikes against Islamic State in Syria.

Protesters filled Parliament Square beneath Big Ben, waving banners and chanting slogans against extending the war against IS.

Demonstrators gathered in Parliament Square (Rachel Megawhat/Breitbart London)

Addressing the crowd, Green Party leader Caroline Lucas said that Islamic State can be stopped, but “bombing doesn’t work”.

Protesters hold a banner in the shadow of Big Ben (Rachel Megawhat/Breitbart London)

A group of protesters also gathered outside the headquarters of the Labour Party after leader Jeremy Corbyn caved to pressure from colleagues and allowed his MPs a free vote on whether to support airstrikes in Syria. He personally opposes the vote and had previously indicated he would whip Labour MPs to support his view.

A pro-Assad supporter joins the demonstration (Rachel Megawhat/Breitbart London)

Around 50 Labour MPs are expected to vote against their leader, though, meaning that victory for the government is all but assured.

(Rachel Megawhat/Breitbart London)

The British government has been considering holding the vote since May’s General Election, but the murder of 130 people in Paris by Islamic State terrorists last month hastened their decision, with some MPs who were previously sceptical now supporting the strikes.

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

Protesters also gathered outside Labour Party headquarters (Rachel Megawhat/Breitbart London)

Police keep guard (Rachel Megawhat/Breitbart London)

Demonstrators waved red flags (Rachel Megawhat/Breitbart London)

One demonstrator harks back to the notable far-left MP Tony Benn(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

(Rachel Megawhat/Breitbart London)

Some messages were cruder than others (Rachel Megawhat/Breitbart London)