Patrick Mercer: Britain can win the battle to build up a powerful military entente cordiale

The first time that we allied in a serious way with the French was during the Crimean War. Many of the British senior officers had cut their teeth fighting against the French, indeed, we even attacked Sebastopol on the anniversary of Waterloo to show how we had patched things up. By 1856, we had soundly beaten the Russians – but by 1859 the French were threatening to invade Britain again!

There have been little bits of co-operation (did I forget to mention the First and Second World Wars and the Cold War?) but what about Suez and the grave difficulties that we faced with the French over the Falklands in 1982?

It's easy to be a little Englander and to belabour the French with a hard backed history book, but does that really answer in today's climate?

Despite the fact that my grandfather and father had both been shot by Germans, I was brought up to believe that the French were our natural foes. But I didn't feel that way when I had my life saved by a French marine in Kosovo. And I didn't feel that way when I had two companies of first class French armoured infantry at my command in Bosnia.

The reality is that if we are going to remain a credible, international military power then we have got to seek alliances and co-operation where we can find them; the prejudices of the past have got to be buried.

When Nicolas Sarkozy spoke to the Prime Minister yesterday, it was be on the clear understanding that it was he who brought his country back into Nato and that Britain and France account for 50 per cent of all defence spending in the EU.

On top of this, there has already been highly successful joint co-operation in campaigns such as the Balkans, and now in Afghanistan/Pakistan.

Indeed, my old Regiment had nothing but praise for the French aircraft that flew in their support in the Helmand Valley, especially when the flak was flying.

First, a treaty is going to be signed over nuclear co-operation. Now that doesn't mean that we will be buying new missiles alongside the French, but it does mean that we will test nuclear components together (despite the risk to British jobs) and that there will be savings to be made in this very expensive field. With the Trident D5 missile not needing any new warheads until at least 2019, this is probably the least contentious part of the deal.

The maritime elements are more thorny. But aircraft carriers are extremely expensive and that we can't really afford to run them.

Each carrier spends about three years being refitted every seven to eight years. So, unless we can have at least three of our own we can't keep one permanently on station. So how do we get around that? Well, we share our resources with the closest, comparable naval power – France – and we try not to think about Trafalgar.

The trouble is, that we are likely to have all sorts of different opinions over foreign policy. I would point to the Falklands campaign in 1982 and the fact that those same Islands are proving to be a hotspot once more. In fact, their defence relies upon submarines and land-based airpower, but the principle remains the same. What if we were called upon to provide a carrier to support French foreign policy with which we did not agree? Remember, only seven years ago, France and Britain differed dramatically over Iraq. So, while the strategy is sound, the devil – as always – will be in the detail.

The third element of the Treaty lies in plans for a joint expeditionary force. While there has certainly been great cooperation in the past, the full integration of ground forces poses all sorts of difficulties.

First, we don't speak the same language and neither nation seems keen to do so, on top of that there are problems with compatibility of equipment, ammunition, logistics, fuel and a host of other things. But, the US General Mark Clark, said that when he gave an order to his army in Italy in 1944, it had to be translated into 17 different languages. But that army, including large British and French elements, finally kicked the Nazis out of the place.

This Treaty is designed to last for 50 years. Of course, there are going to be practical and cultural difficulties, but the young men and women on both sides of the Channel who are being asked to do the fighting and dying today don't, I suggest, care too much for the mistakes of the past.

Of course, we have got to heed history, but Nato is the alliance to which we belong and France is our most powerful partner in it. We have got to make it work: vive l'entente.

Patrick Mercer is a former soldier and the Conservative MP for Newark.