Just under a month ago, my colleagues and I on the Foreign Affairs Committee published a Report entitled “extension of offensive British military operations to Syria”. We took evidence from a range of experts including academics, former military, lawyers, Syrian groups and the Foreign Secretary among others.

As a result of those sessions we looked at a number of areas including the legal basis, political challenges and the likely outcomes of any military action. Based on that evidence our Committee, with a Conservative majority, found that the case for military action was not made. As a direct result of our Report the Prime Minister made the unprecedented move of responding to its findings direct in the House of Commons on Thursday.

It is easy to see why MPs remain queasy about war. In the past Parliament gave approval to go to war in Iraq and Libya among other conflicts. In both cases that decision proved fateful leaving both countries in a worse state than we found them. It has been argued with good cause that the vacuum left in parts of Iraq and Libya allowed radical organisations including Daesh - also known as Islamic State (IS) - to thrive. It is little wonder that that Julien Barnes-Dacey a Middle East expert at the European Council on Foreign Relations told us “I really fail to see how airstrikes against IS will not do more harm than good”.

The Prime Minister therefore had a big job in terms of convincing MPs, like me, sceptical about the efficacy of military action. That doubt remains and in my view he failed leaving significant questions unanswered.

Firstly there is consensus that ground troops are needed to consolidate any air strikes. However there is no evidence of any being ready to make the advances needed particularly Raqqa where Sunni Arab troops will be needed. The Prime Minister’s claim that there are 70,000 moderate opposition troops appears to have little basis and our Committee found there was “little chance of a legitimate and functioning ally emerging from the chaos soon”.

Ground troops are absolutely central to any success and their absence one of the reasons we rejected military action. The Prime Minister will need to provide more evidence of this assertion. One commentator has already asked whether “70,000 troops is the new 45 minutes” (with reference to Tony Blair’s claims about WMD before the Iraq war). I hope not.

Over and above that key element the Prime Minister also failed to set out the case for war in other regards such as legality where there is a clear question mark. Furthermore is the military necessity of UK involvement. So far 13 coalition partners have carried out over 2,500 sorties against Daesh targets in Syria. There is little evidence that any UK action would have anything other than a very “marginal effect” with the Prime Minister’s claims over the missile Brimstone being dismissed not least because the Saudis are already said to be deploying the technology in Syria.

There is also a very substantial point concerning the development of a long term peace strategy that is ultimately the best way to destroy Daesh. Progress in Vienna is welcome but there is a long way to go.

There is more to this conflict than adding the UK’s eight planes to the crowded skies above Syria. The UK could lead in key areas such as disrupting Daesh’s finances and its ability to spread its poisonous propaganda through social media. Our witnesses also argued that since the UK “hasn’t prejudiced its position” in Syria any military action could reduce its diplomatic capacity to create a route to a solution.

No one questions the need to tackle Daesh and it is right that we debate the best means of ending their murderous tyranny. The Prime Minister has not made the case for war and is missing an opportunity to show leadership in helping bring the conflict to an end.

The Foreign Affairs Committee rightly set the bar high for military action. It is a pity that the Prime Minister has failed to respond adequately to that case.

Stephen Gethins is the SNP’s member of the Foreign Affairs Committee and MP for North East Fife