The Prime Minister will say the UK joined the United States and France in co-ordinated strikes following the chemical weapons attack in Douma to ‘alleviate further humanitarian suffering’.
Mrs May will ask for an emergency debate to allow more time for discussion in a nod to the fury among MPs at not being consulted.
She will say: ‘There is broad based international support for the action we have taken.’
Drawing links to the Salisbury spy attack, she will add: ‘Let me be absolutely clear: we have acted because it is in our national interest to do so.
‘It is in our national interest to prevent the further use of chemical weapons in Syria – and to uphold and defend the global consensus that these weapons should not be used.
‘For we cannot allow the use of chemical weapons to become normalised – either within Syria, on the streets of the UK or elsewhere.’
International Development Secretary Penny Mordaunt this morning opposed calls to give Parliament greater powers over military interventions.
Ms Mordaunt told BBC Radio 4’s Today programme: ‘To take a decision on whether something is legally justified, and whether what we are actually intending on doing in terms of targets is appropriate, you would need to know information that could not be shared with every MP.
‘And so, outsourcing that decision to people who do not have the full picture is, I think, quite wrong. And, the convention that was established, I think is very wrong.
‘I support governments being able to take those decisions, Parliament should hold government to account for that decision.’
Foreign Secretary Boris Johnson insisted the strikes – co-ordinated with action by the United States and France – were ‘right for the UK and right for the world’.
The Prime Minister spent Saturday evening speaking to world leaders to explain why Britain had joined forces with France and the US and will insist the three nations are ‘not alone’ in believing it was the ‘right thing to do’.
Germany, Italy, Canada, Australia and European Council President Donald Tusk have ‘all have expressed their support for the actions that Britain, France and America have taken’, the PM will add.
United Nations Security Council-mandated inspectors have probed previous attacks and decided Bashar Assad’s regime was responsible four times, MPs will be told.
She will add: ‘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.
‘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.’
Welcome the news of UK military strikes against major chemical weapons facilities in Syria alongside our US and French allies. The world is united in its disgust for any use of chemical weapons, but especially against civilians
— Boris Johnson (@BorisJohnson) April 14, 2018
Four Royal Air Force Tornado GR4s joined the co-ordinated missile strikes at 2am on Saturday, launching Storm Shadow missiles at a base 15 miles west of Homs.
The United States is preparing to impose sanctions on Russia for ‘covering up’ the actions of the Assad regime.
Trump: ‘Mission accomplished’
Donald Trump tweeted ‘Mission Accomplished’ on Saturday after US, French and British planes and ships launched more than 100 missiles nearly unopposed by Syrian air defences.
However, he came under attack for his choice of words and has now defended his use of the phrase ‘Mission Accomplished’.
The US president said that ‘it is such a great military term, it should be brought back’.
A perfectly executed strike last night. Thank you to France and the United Kingdom for their wisdom and the power of their fine Military. Could not have had a better result. Mission Accomplished!
— Donald J. Trump (@realDonaldTrump) April 14, 2018
The Syrian raid was so perfectly carried out, with such precision, that the only way the Fake News Media could demean was by my use of the term “Mission Accomplished.” I knew they would seize on this but felt it is such a great Military term, it should be brought back. Use often!
— Donald J. Trump (@realDonaldTrump) April 15, 2018
In an early-morning tweet, President Trump said the strike was ‘perfectly carried out’ and that ‘the only way the Fake News Media could demean was by my use of the term ‘Mission Accomplished’.
He added that he knew the media would “seize” on the phrase, but said it should be used often.
Syria’s President Bashar Assad said the Western air strikes against his country were accompanied by a campaign of ‘lies’ and misinformation at the UN.
He spoke on Sunday to a group of visiting Russian politicians, and his comments were carried by state media.
Assad and Russia deny using chemical weapons, the trigger for the strikes early on Saturday.
The air strikes have angered Moscow and today’s debate comes amid reports that Russia has launched a ‘dirty tricks’ campaign in response to the strikes.
Whitehall sources have confirmed a 20-fold increase in ‘disinformation’ spread by Kremlin-linked social media ‘bot’ accounts since the strikes, according to The Daily Telegraph.
Foreign Secretary Boris Johnson said the UK has to ‘take every possible precaution’ to prepare for possible revenge cyber attacks on targets like the NHS and electrical facilities.
Labour refuse to back strikes
Jeremy Corbyn has called for the introduction of a War Powers Act to stop governments launching military action in most circumstances without the backing of the Commons.
The Labour leader said chlorine has been used by ‘a number of parties in the conflict’ in Syria as a weapon and questioned the legality of the airstrikes.
Asked if there were any circumstances in which he would back air strikes in Syria, Mr Corbyn told BBC One’s The Andrew Marr Show: ‘I can only countenance involvement in Syria if there is a UN authority behind it.
After @Theresa_May’s attack on Syria, I have called for a Wars Powers Act so that governments are held to account by Parliament for what they do in our name.
— Jeremy Corbyn (@jeremycorbyn) April 15, 2018
‘If we could get to a process in the UN where you get to a ceasefire, you get to a political solution, you then may well get to a situation where there could be a UN force established to enforce that ceasefire.’
Writing in The Guardian today, he added: ‘The military action at the weekend was legally questionable.
‘The Government’s own justification, which relies heavily on the strongly contested doctrine of humanitarian intervention, does not even meet its own tests.
‘Without UN authority it was again a matter of the US and British governments arrogating to themselves an authority to act unilaterally which they do not possess.’
Shadow foreign secretary Emily Thornberry said taking military action against Bashar Assad’s regime had been the ‘wrong thing to do’.
Shadow attorney general Baroness Chakrabarti questioned the Government’s justification for the air strikes, telling BBC Radio 4’s Today programme: ‘You can’t use force under international law just to punish Syria for bad behaviour.
‘You have to actually be using urgent, necessary and proportionate force. And you have to do it with the will of the world behind you.’
She added: ‘I think that Parliament should have been recalled before the strike. Some people will suspect that that didn’t happen because of governmental concerns that they couldn’t get the vote in Parliament. And that to me is not a good enough reason.’
Links to Salisbury
Mrs May spoke in Downing Street in the hours after the blitz and insisted the action was a limited and targeted strike to degrade and deter the Syrian government.
But she also drew a link with the nerve agent attack on Russian former spy Sergei Skripal and his daughter Yulia in Salisbury.
The Prime Minister will tell MPs on Monday that the strikes were in the national interest because the use of chemical weapons cannot be normalised, including in the UK.
France persuaded Trump to strike
France persuaded Donald Trump to stay in Syria and launch air strikes as punishment for the alleged chemical weapons attack, French president Emmanuel Macron said.
Macron said the US, Britain and France had ‘full international legitimacy to intervene’ with the strikes, to enforce international humanitarian law.
He added: ‘It was retaliation, not an act of war. Ten days ago president Trump wanted the United States of America to withdraw from Syria. We convinced him to remain.’