Protests have taken place in London against the UK joining US-led air strikes on Islamist State militants in Iraq.
MPs are set to vote on military action this Friday.
Parties from across the political spectrum are expected to vote in favour of Britain’s first military action since a 2011 aerial campaign in Libya.
“Now of course it is absolutely right that we should learn the lessons of the past especially what happened in Iraq a decade ago. But we must not be so frozen with fear that we don’t do anything at all. Isolation and withdrawing from a problem like ISIL will only make matters worse,” British Prime Minister David Cameron said at the United Nations this week.
Friday’s vote only refers to military action in Iraq.
The British Prime Minister has held back from joining the US-led coalition bombing ISIL targets after suffering a humiliating defeat last year when MPs rejected air strikes against Syrian government forces.