It has sparked a huge political row, with many MPs appalled the PM did not seek the backing of Parliament before pressing ahead with military action against the Assad regime.
We’ll hear more from the government tomorrow, when May makes a statement in the Commons.
Jeremy Corbyn made his views on the intervention very clear on the Andrew Marr Show, accusing May of being too quick to follow Donald Trump’s lead and using policy “made up on Twitter”.
He was backed up by his shadow justice secretary, Richard Burgon, on Sky’s Sunday With Paterson.
Corbyn wants the international Organisation for the Prohibition of Chemical Weapons to take the lead in investigating exactly what went on in the rebel-held town of Douma, where civilians were targeted in a suspected chemical attack.
He believes humanitarian grounds alone did not provide enough of a basis for the UK to launch air strikes and said he could not support such action unless it had UN backing (which Russia could still veto).