Jeremy Corbyn urged Theresa May to postpone what he described as the “legally questionable” Syrian air strikes during last-minute talks with Downing Street Friday night.
The Labour leader said the missile attack by Britain and the USA on Syria will make it less likely the Assad regime will be held accountable for war crimes.
He also criticised Theresa May for “taking instructions from Washington” and said the Prime Minister should have obtained Parliament’s backing before launching the strikes.
Speaking after the US, UK and France bombed multiple Syrian government targets in an early morning operation aimed at destroying alleged chemical weapons sites, Mr Corbyn said: “Bombs won’t save lives or bring about peace.
“This legally questionable action risks escalating further, as US defence secretary James Mattis has admitted, an already devastating conflict and therefore makes real accountability for war crimes and use of chemical weapons less, not more likely.”
Mr Corbyn added: “Britain should be playing a leadership role to bring about a ceasefire in the conflict, not taking instructions from Washington and putting British military personnel in harm’s way.
“Theresa May should have sought parliamentary approval, not trailed after Donald Trump. The Government should do whatever possible to push Russia and the United States to agree to an independent UN-led investigation of last weekend’s horrific chemical weapons attack so that those responsible can be held to account.”
The leader of the opposition was visiting to Huddersfield on Saturday and spoke to his Conservative counterpart late on Friday.
He said: “I had a late night conversation with the Prime Minister and my whole point is that Parliament should be consulted, parliament should be allowed to take a view on this but, instead, the strikes were launched last night.
“Parliament is in session on Monday. She could have come to Parliament on Monday to discuss the whole situation. Instead, they’ve launched these strikes.
“She claims there’s a legal basis for it.
“I’ve asked her in a letter I’ve just to sent her this morning to publish in full the legal basis and justification for it.”
During the Yorkshire visit, Mr Corbyn added: “Also, why she hasn’t heeded the words of Antonio Guterres – the general secretary of the United Nations – who wanted the strikes to be stopped, who wanted the UN charter to be observed, and give time for the OPCW to do its inspection of chemical weapons in Syria?
“And, also, to work again to get a ceasefire in Syria so that no more people are killed in this ghastly civil war in Syria.”
Profile | António Guterres
He said: “We’ll be pushing for publication of the legal advice that the government has given.
“We will be demanding that the government goes back to the United Nations with the support of the Swedish government, or in support of the Swedish government in order the get a new UN resolution and bring Russia and the United States together along with Iran, Saudi Arabia, Israel, Turkey – all the neighbouring states there. This civil war is ghastly. It’s killed hundreds of thousands.
“It’s driven millions into refuge in other countries and the chemical weapons are obviously appalling and disgusting and completely illegal within international law.”
Mr Corbyn said there was only a legal basis for action if there was a direct threat to the UK.
He said: “You could only do it under the basis of self-defence – if there was a direct threat to us, and there wasn’t.”
Intervention in Syria | Read more
Stewart McDonald, the Scottish National Party spokesman for defence, said UK forces had been engaged in “gesture bombing with no major international consensus”.
“Most worrying is that she has acted at the behest of presidential tweets and sidelined Parliament,” he said on Twitter.
“What does this new bombing campaign do to help move Syria towards peace? Nothing.
“Instead, it has the potential to dangerously complicate the war, making matters on the ground worse for the people that the strikes are supposed to help. There is no peace strategy.”
Owen Smith, the Shadow Secretary of State for Northern Ireland, also attacked the decision, writing on Twitter: “The House of Commons is elected to represent the people of our country and to hold our Executive to account.
“Parliament should have been recalled and consulted before we engaged in this military action in Syria.”
But Carwyn Jones, Labour’s First Minister of Wales, backed the action, as long as it was part of a wider plan to bring peace to the region.
Mr Jones said: “I spoke with the PM late last night about the action in Syria. I offered my support to any intervention that could prevent a further atrocity, but it is vital that any action forms part of a wider long-term plan for the region.
“I have urged the Prime Minister to do all she can to avoid civilian casualties given the complicated picture on the ground in Syria, and she has given me assurances in that regard.
“Our thoughts today are with our service personnel and the people of Syria, who have endured beyond all measure.”
At a Pentagon briefing shortly after President Trump announced strikes had taken place, Gen Joseph Dunford said a scientific research facility in Damascus, allegedly connected to the production of chemical and biological weapons, had been hit, along with a chemical weapons storage facility west of Homs and a chemical weapons equipment storage site and command post, also near Homs.
Syrian state television said government forces had shot down more than a dozen missiles, and claimed only the research facility in Damascus had been damaged. It said three civilians had been injured in Homs.