Air strikes in Syria were about saying "enough is enough" over the use of chemical weapons, Foreign Secretary Boris Johnson has said, BBC reports.
Mr Johnson said the action by the US, UK and France would not "turn the tide" of the conflict and was not about regime change.
But he said he hoped it would act as a deterrent to more "barbaric" chemical attacks.
Labour leader Jeremy Corbyn has questioned the legality of the action.
He called for new legislation to ensure MPs get a vote before future military action is taken, and said he would only back intervention in Syria if the United Nations backed it.
Conservatives said this would never happen due to Russia using its veto at the UN.