Theresa May will on Monday seek an emergency debate in the House of Commons about last weekend's air strikes against Syria, giving MPs a chance to express their view on the action in a vote.
The British prime minister has faced criticism for her failure to seek prior parliamentary authorisation for Britain's participation in the bombardment, alongside the United States and France.
Ms May will tell MPs she took the action to alleviate further humanitarian suffering in Syria caused by chemical weapons attacks and that it was in Britain's national interest to do so. She will say United Nations inspectors found Syrian president Bashar al-Assad's government responsible for four previous chemical weapons attacks and that she is confident it was "highly likely" to have been behind last week's attack in Douma, which killed up to 75 people.
Vladimir Putin, in particular, stressed that if such actions were committed in violation of the UN charter continue, then it will inevitably lead to chaos in international relations
“We are confident in our own assessment that the Syrian regime was highly likely responsible for this attack and that its persistent pattern of behaviour meant that it was highly likely to continue using chemical weapons,” she will say.
“Furthermore, there were clearly attempts to block any proper investigation, as we saw with the Russian veto at the UN earlier in the week. And we cannot wait to alleviate further humanitarian suffering caused by chemical weapons attacks.”
Kremlin warning
The US, France and Britain launched 105 missiles against Syria on Saturday, targeting three sites they said were linked to a chemical weapons programme. Russian president Vladimir Putin warned on Sunday that further western attacks on Syria would bring chaos to world affairs.
A Kremlin statement said Mr Putin and his Iranian counterpart, Hassan Rouhani, agreed during a telephone conversation that the air strikes had damaged the chances of achieving a political resolution of the conflict in Syria.
“Vladimir Putin, in particular, stressed that if such actions were committed in violation of the UN charter continue, then it will inevitably lead to chaos in international relations,” the statement said.
EU foreign ministers will discuss the air strikes in Luxembourg on Monday, amid concerns by some member states about the legality of the operation without UN approval, and about the categorical attribution of responsibility to Syria ahead of reports from the inspectors on the ground.
I think everyone knows that we sent a strong message, and our hope is that they listen to it
Ireland will not condemn the air strikes and Irish sources said there was no division within the EU about the need to deter chemical attacks and that the Assad regime was involved in wholesale slaughter of its own people.
Further action
Some other member states are unhappy with a statement issued on behalf of the European Council on Saturday, which appeared to declare the EU's wholehearted support for the operation by the US, France and Britain.
London and Washington have played down the prospect of further military action against Syria but Nikki Haley, the US ambassador to the UN, said there would be fresh sanctions against Russian companies which have helped the Assad regime's chemical weapons programme.
“They will go directly to any sort of companies that were dealing with equipment related to Assad and chemical weapons use. I think everyone is going to feel it at this point. I think everyone knows that we sent a strong message, and our hope is that they listen to it,” she told CBS News on Sunday.
UN chemical weapons inspectors who arrived in Syria at the weekend have promised to investigate what happened in Douma despite the air strikes against chemical weapons installations.
Russia and Syria invited the inspectors to investigate the attack last week, hoping that the US and its allies would delay their bombardment until after the investigation.
