Defence Secretary Sir Michael Fallon has sidestepped questions over whether Theresa May will push for military action against the Assad regime in Syria.

Repeatedly asked over whether the Prime Minister would attempt to win a parliamentary vote for action against Assad, he would only say she already had authority for strikes against Isis.

Foreign Secretary Boris Johnson has suggested the UK could back military operations targeting the Assad regime, if asked by the US and that it might do so without further parliamentary approval.

There have also been reports that if Theresa May wins the election on June 8 she could attempt to push a motion through the House of Commons to gain backing for action, leading Labour to warn that a Tory win will mean escalating the country’s civil war.

Asked if Ms May would push for a vote for action against Assad, Sir Michael said: “No we’ve already had a vote allowing us to take actions in Syria. The RAF are flying day and night in the battle against Daesh.

“We won that vote in December 2015 and we’ve been playing a prominent part.”

Pushed further on BBC’s Radio 4 Today programme on whether there would be a vote for action against Assad, as opposed to simply Isis, he said: “We are not planning another vote in the House of Commons, we already have the authority we need to deal with Daesh terrorism in both Iraq and Syria.”

Aleppo before the Syrian Civil War Show all 12 1 /12 Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man crosses a street in Aleppo, December 12, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A vendor sits inside an antique shop in al-Jdeideh neighbourhood, in the Old City of Aleppo, December 12, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A view shows part of Aleppo's historic citadel, overlooking Aleppo city, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A view shows part of Aleppo's historic citadel, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Visitors walk inside Aleppo's Umayyad mosque, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk inside the Khan al-Shounah market, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man walks past shops in al-Jdeideh neighbourhood, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk along an alley in al-Jdeideh neighbourhood, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Visitors tour Aleppo's historic citadel, Syria December 11, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A general view shows the Old City of Aleppo as seen from Aleppo's historic citadel, Syria December 11, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk near Aleppo's Bab al-Faraj Clock Tower, Syria October 6, 2010 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man stands inside Aleppo's historic citadel, overlooking Aleppo city, Syria December 11, 2009 Reuters

Mr Johnson said last week “it will be very difficult for us to say no” if the US asks for British support against Assad forces and hinted that it may be taken without a Commons vote, saying “how exactly we were able to implement that would be for the Government, the Prime Minister”.

Sir Michael would not engage with what would happen if the US asked Britain for backing against Assad, saying it is a hypothetical question, but answered again: “No, we’re not planning a vote, we have the authority we need to deal with Daesh terrorism in Syria as in Iraq.”

Shadow Foreign Secretary Emily Thornberry said wading into a war against the Assad regime would “risk open conflict between our armed forces and those of Russia and Iran” and could lead the UK to repeat the mistakes of the Iraq war.