James Gray is a member of the Defence Select Committee, MP for North Wiltshire, and author of Who Takes Britain to War?

It is said that the Prime Minister is awaiting the outcome of the Labour Leadership election before trying to secure Parliamentary approval to extend the Iraq airstrikes to Syria. Jeremy Corbyn, of course, is unlikely to be a very enthusiastic supporter of the idea which, depending on the view of the SNP, may well present David Cameron with a real problem.

For it is a fairly widely-accepted wisdom that using air strikes against Daesh in Iraq, but not allowing them against Daesh in Syria is an obvious strategic absurdity. The border is porous, with the enemy moving backwards and forwards at will, their main planning HQs being just over the border in Syria. Yet our planes must turn back as soon as they near the imaginary and outdated Sykes-Picot Line. If Daesh are the enemy and a threat to us all, then surely we should strike them whenever and wherever we can. However, the niceties of Parliamentary procedure are currently preventing us doing so.

Since Tony Blair’s Commons vote to invade Iraq in 2003, it has become the widely-held view that there should never be any kind of military action without it being approved by a prior substantive vote in the House.

But for hundreds of years prior to that, acting under the ancient Royal Prerogative, military action had been a matter for the Prime Minister and the Cabinet, with Parliament subsequently holding them to account for their actions. Parliament was “informed and advised” of their military decisions rather than “being consulted” on them. Yet in 2003, by a clever piece of Blairite Parliamentary emasculation, he used his whips (and ours) to persuade a reluctant Commons to approve his pre-set plans, thereby preventing us from questioning or criticising them thereafter.

Now you can perfectly well argue that the days of Prime Ministers taking this most devastating of all decisions – to go to war- under an ancient right handed to him by the Monarchy should be long gone. We live in a democracy. Surely it should be the tribunes of the People – MPs – who properly take these decisions? And I am a strong advocate of strengthening Parliament vis-à-vis the Executive in every possible way.

Yet the truth is that if the use of military force is allowed to be political (which it must be if it needs a majority in a possibly marginal House of Commons), then it cannot be strategic. Should the Prime Minister be doing what is right for the peace and the people of the world? Or should he have primary concern for its popularity in Parliament? The former Chief of Defence Staff, David (now Lord) Richards was quoted in this weekend’s paper attacking Cameron over his actions in Libya and Syria – even going so far as to suggest that the current refugee tide may be linked to it. There may be some truth in that. The Government does seem to have got itself into a terrible tangle over the process by which we make use of our military.

Giving Parliament the final say over warfare politicises the war; it means that possibly sensitive intelligence has to be made public; it removes any element of surprise, delays decision-making and, in a host of other ways, makes the effective conduct of military force extremely difficult, if not virtually impossible. Now even if you think all this may be a good thing, I would hope that you would agree it also has a devastating impact on our ability to project power for the good of the world. Diplomacy without arms is like music without an orchestra.

In other words, would it not be perfectly reasonable for the Prime Minister to authorise air strikes against Daesh in Syria, and to have inform Parliament of it, and answer our questions and criticism afterwards? Should Parliament’s job not be to hold the Prime Minister and Executive to account for what they have done rather than becoming a party to it?

Or could we not square the circle of giving the Cameron the necessary freedom to act militarily while still ensuring the primacy of Parliamentary decision-making? Would it not be better for the ‘Royal Prerogative’ which Prime Ministers relied on so effectively in dozens of wars over hundreds of years, to be replaced by a ‘Parliamentary Prerogative’?

Parliament would write into law the acceptable reasons for military action, the ways in which wars should be fought, and the ways in which they should be concluded. (The three parts of the old philosophy of the ‘Just War’). Such a statute would then allow the Prime Minister to act as he always done. He would be doing so with the full authority of Parliament, yet removing the necessity to consult we backbenchers in detail about the proposed military action. Is it not time for a Parliamentary Prerogative to replace the ‘Royal’ one?