Labour leader Jeremy Corbyn has accused PM Theresa May of "waiting for instructions" from US president Donald Trump on how to respond to the use of chemical weapons in Syria.

Mr Corbyn also called for an independent UN-led inquiry into the devastating air strike in Douma last Saturday that killed a reported 75 civilians and injured 500 more, presumed to have been carried out by the Bashar al-Assad regime.

"Further UK military intervention in Syria's appalling multi-sided war risks escalating an already devastating conflict," he said.

"The government appears to be waiting for instructions from President Donald Trump on how to proceed. But the US administration is giving alarmingly contradictory signals.

"Even US defence secretary James Mattis has said we 'don't have evidence' and warned further military action could 'escalate out of control'."

Rather than looking to Washington for leadership, Mr Corbyn urged the government to have the courage of its convictions and press for a non-partisan investigation into the atrocity.

"Ministers should take their proposals, such as they are, to parliament. And Britain should press for an independent UN-led investigation of last weekend's horrific chemical weapons attack so that those responsible can be held to account," he said.

"Rather than further military action, what is urgently needed is a coordinated international drive to achieve a ceasefire and a negotiated settlement under UN auspices. The humanitarian priority must be to halt the killing on all sides.

"The need to restart genuine negotiations for peace and an inclusive political settlement of the Syrian conflict, including the withdrawal of all foreign forces, could not be more urgent. We must do everything we can, no matter how challenging, to bring that about."

Jeremy Corbyn condemns Donald Trump's rhetoric on Syria: 'More war will not save life'

Downing Street is currently understood to be planning a co-ordinated response to the Assad regime with coalition allies the US and France, an issue complicated by Russia's support for the Syrian government and the Kremlin's already fraught relations with the international community over the alleged poisoning of ex-spy Sergei Skripal on British soil.

President Trump risked inflaming an already tense situation earlier this week when he tweeted that Russia should "get ready" for a coalition missile strike on Syria.

Ms May's cabinet met for two hours yesterday to discuss strategy and agreed a need to "take action" after the PM denounced the incident as a "shocking and barbaric act".

She later spoke to President Trump who "agreed that the Assad regime had established a pattern of dangerous behaviour in relation to the use of chemical weapons", according to a Downing Street spokesperson.

Ms May is not obliged to seek parliamentary approval before launching a military intervention but Mr Corbyn has insisted that the House of Commons must be consulted before any action is approved.

Emmanual Macron says France has prood the Assad used chemical weapons in Syria