The UK has joined the USA and France in carrying out air strikes to suspected Syrian chemical weapons facilities on Friday. Theresa May’s decision for Britain to join the strikes on Syria has met with mixed reactions.

The Prime Minister said she judged the operation to be in Britain’s national interest, adding that there was “no practicable alternative to the use of force”.

Her decision came despite demands from opposition parties that Parliament was consulted before any military action was launched.

Foreign Secretary Boris Johnson backed the PM, writing on Twitter that the world was “united in its disgust for any use of chemical weapons, but especially against civilians”.

Other Tory MPs also publicly voiced their support, with Thornbury and Yate MP Luke Hall saying: “Speed is essential. A clear signal to anyone who believes they can use chemical weapons with impunity.”

Newark MP Robert Jenrick said: “My thoughts are with our servicemen and women – and those of our US and French allies. The cost to President Assad of using heinous chemical weapons must be higher than any perceived benefit. I strongly support the PM’s decision.”

Also backing the joint air strikes by the US, the UK and France was NATO Secretary General, Jens Stoltenberg. He said that the strikes would reduce Syrian President Bashar al-Assad’s regime ability to further attack the local population with chemical weapons, according to a statement.

“NATO has consistently condemned Syria’s continued use of chemical weapons as a clear breach of international norms and agreements,” Stoltenberg said in a statement.

“The use of chemical weapons is unacceptable, and those responsible must be held accountable,” he added.

Meanwhile, UN Secretary-General Antonio Guterres has urged the members of the organisation to show moderation in the prevailing “dangerous” climate and to respect international law.

Guterres’ remarks came during a Security Council meeting on Friday, shortly before the strikes were launched in response to the alleged use of chemical weapons in the Syrian town of Douma on April 7.

“I urge all member states to act responsibly in these dangerous circumstances,” Guterres said.

The Council has met four times this week to assess the Syrian situation but the sessions have ended without any agreements being reached.

The debates have exposed the deep divisions between the US and Russia on the conflict, which led Guterres to say that “the Cold War is back – with a vengeance”.

Others who were against the strikes included 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.”

Scottish First Minister Nicola Sturgeon also said questions remained about how peace could be brought to Syria.

She tweeted: “My first thoughts this morning are with the service personnel called to action.

“Syria’s use of chemical weapons is sickening – but the question that the PM has not answered is how this action, taken without parliamentary approval, will halt their use or bring long-term peace.”

Lib Dem MP Tom Brake tweeted: “Theresa May had no right to deploy British forces in #Syria without Parliament’s approval. There was no threat to the UK. Nor does she have a majority in Parliament.

Labour Party Leader Jeremy Corbyn said Bombs won’t save lives or bring about peace. In a statement he 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.

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.”