Until now the U.K. limited itself to targeting ISIS in Iraq and previously refused to hit ISIS strongholds in Syria on the grounds that it does not have the necessary authorization from the United Nations or the domestic government.
Members of parliament (MPs) clashed for several hours over the government's motion to strike ISIS in Syria. Prime Minister and leader of the Conservative Party David Cameron made the case to parliament that bombing ISIS in Syria will help to ensure the security of the British people and degrade ISIS's ability take territory.
Cameron argues there are 70,000 fighters in Syria who oppose ISIS and will be helped by the U.K.'s intervention. The source for this figure is the U.K.'s Joint Intelligence Committee.