Although a minority of MPs expressed their opposition to British air strikes against Isis, there were concerns over whether RAF Tornado jets flying combat missions over Iraq were the answer to the rapid advance of Isis.
Politicians with previous experience of armed conflict, such as Adam Holloway MP, remained unconvinced. The Conservative MP for Gravesham and a former army officer who served in the Gulf War said: "There is no simple solution to any of this, but the answer does not come from something military that is led by the West. It comes from something political that is led by people within the region.
"It should include long-term political vision otherwise, step-by-small step, we are going to enter a much darker age of war and radicalisation."
Another Tory MP, Sir Edward Leigh said: "Never have so few been asked by so many to achieve so much with no clear aim in sight… We have caused this mess and we should apologise to the people of the region for it."
Alan Duncan, former international development minister warned caution: "In my mind, [British military action] shows every sign of being neither easy or conclusive."
One of the first peers to openly reject air strikes against Isis in Iraq, Baroness Falkner and the Lib Dem spokeswoman for foreign affairs in the Lords, voiced her doubts over how British involvement in Iraq was necessary: "The threat to British people on the streets of the UK is not going to be ameliorated by another foreign war," she said.
The Stop the War Coalition has warned that bombing raids will only increase hatred of the West. "Escalating Western military intervention will do nothing to stop [ISIS] but will create more suffering and further destabilise the region," said a spokesperson.
Some pundits even believe that combat missions against the Islamic State will further inflame the conflict. Writing in the Daily Beast, Earth Institute director Jeffrey Sachs and the Quakers' Michael Shank said: "Bombing is most likely to create further instability, spiralling violence, and new recruits for radical military groups."