Jeremy Corbyn has claimed Theresa May’s decision to launch air strikes in Syria is “policy made up by Twitter”.
The Labour leader told the BBC’s Andrew Marr Show he believed Parliament should have been given a vote on military intervention and that the prime minister had been too keen to “follow Donald Trump’s lead”.
“She could have recalled Parliament last week or she could have delayed until tomorrow when Parliament returns itself,” he said.
“There is precedent over previous interventions where Parliament has had a vote and what I think what we need in this country is something more robust, like a War Powers Act, so that governments do get held to account by Parliament for what they do in our name.”
He added: “It looked awfully to me that the PM was more interested in following Donald Trump’s lead than anything else. This is policy made up by Twitter - and we don’t want that.”
Corbyn, who voted against UK military attacks on ISIS in 2014, said he could only countenance intervention in Syria if there was “UN authority behind it” and that taking action on humanitarian grounds alone was a “legally debatable concept”.
Four RAF jets joined French and American forces over the weekend in attacking the Assad regime over the alleged chemical attack on civilians in the rebel-held town of Douma.
Corbyn called for the Organisation for the Prohibition of Chemical Weapons to be given the chance to report on the incident and that Assad and “any other group” found to be responsible should be “confronted with evidence”.
He said a political solution needed to be found and that military strikes would not prevent further loss of life.
“It can be done. It’s hard work and it takes patience, but surely that is better than the escalation of this into a proxy war,” the Labour leader added.
“The killing has to stop. A ceasefire has to come into place.”
Boris Johnson told the programme the government’s action was the right course to take and that Theresa May would make a statement on her decision in Parliament on Monday.
“The overwhelming purpose of this mission was to send a message,” the foreign secretary said.
“Its primary purpose was to say no to the use of barbaric chemical weapons. We must hope it is a deterrent and I believe it has been a successful, timely, appropriate and commensurate mission.”