It's less than a year since Parliament decided not to use military force against Syria. I still think that was the right decision, since no-one could really contemplate the consequences had we done so.

Yet I have grave misgivings about the way in which that decision was reached. For, surprising as you might think it, August 29 2013 was only the second occasion on which Parliament had voted on war. (The first time – in 2003 – we voted to go to war with Iraq. That’s hardly a very good advert for Parliament deciding these matters!)

For hundreds of years prior to that it was not Parliament who decided to go to war. It was the prime minister and cabinet. They acted under the ancient Royal Prerogative, by which the Monarchy handed a large number of their functions over to the Government. Parliament was informed and advised of their decision rather than being consulted on it. Now you could 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. However giving Parliament the final say over warfare politicises it would mean that possibly sensitive intelligence would have to be made public. It removes any element of surprise, delays decision making, and in a host of other ways would make the effective conduct of military force virtually impossible.

So I have come up with a new idea. It’s the subject of a book I have written entitled Who Takes Britain to War? which will be published shortly by Stroud-based publishers, The History Group. In the book I propose that the Royal Prerogative which prime ministers relied on so effectively in dozens of wars over hundreds of years should now 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 (s)he has always done, but (s)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.