By Patrick Wintour, Political Editor

Guardian – 2 October 2015

David Cameron's already complex route to securing a Commons vote in favour of UK airstrikes in Syria has become even more difficult as a result of the Russian intervention in the past 48 hours, senior MPs believe. It had been expected that Cameron would come back to the Commons for a vote this month, but the unexpected Russian intervention and the continuing political divisions inside the Labour party make that timetable less likely.

Labour finished its conference agreeing to a statement not ruling out support for UK involvement in airstrikes subject to UN authorisation, but with senior figures admitting that any vote was likely to be treated by Labour MPs as a conscience vote. The immediate dilemma facing the UK was whether it would be forced to accept that the price of the ejection of Islamic State from northern Syria was the strengthening of President Bashar al-Assad. Cameron has always insisted that there can be no long-term settlement unless Assad goes, even if he remains during a transition. The Labour frontbench also recognises that Assad is the cause of most deaths in Syria.

One senior Tory frontbencher said:

"Russia has filled a four-year-old vacuum. We have been totally outmanoeuvred. There is a danger that there will be a settlement across Syria and Iraq that is brokered by Iran and Russia, and not anyone else."

There was also concern at reports that Vladimir Putin was targeting the al-Nusra Front and so-called Syrian moderate forces – Assad's opposition – in its initial raids rather than Isis. Russia appears to show little interest in cooperating in the removal of Isis, making the political and military situation extremely dangerous. UK sources said an early objective would be to ensure some cooperation over the use of Syrian airspace by rival attack aircraft.

In a sign of the continued hostility to airstrikes on the Conservative benches, Julian Lewis, the Conservative chairman of the Defence Select Committee, argued that the Russian involvement made the already largely symbolic participation of the UK air force even more symbolic. He has long argued that Britain needs to recognise that Assad will have to remain in power if the primary goal of ejecting Isis is to be achieved.

Lewis said the chances of a moderate Free Syrian Army becoming a key factor in the conflict was

“boy scout childish politics".

He also argued:

"The history of the last decade ought to have taught us that the best we can expect is a choice between greater or lesser evils. The Prime Minister has rightly identified Daesh [Isis] as a serious threat to our interests. This makes more sense than trying to oust Assad, regardless of the danger of an Islamist takeover were he to fall."

Lewis argued airstrikes alone would not solve anything.

"Eliminating Daesh requires an integrated military strategy based on viable ground forces. Without such forces, airstrikes cannot be decisive. Adding RAF sorties to those already undertaken in Syria by the United States would simply be symbolic – a gesture as impermanent as a sandcastle in the desert."

There is also bitterness in Conservative circles that Cameron's inability to win Commons support for airstrikes against Assad two years ago has contributed to the vacuum that Putin has rushed to fill …