Whether those who campaign for the UK to leave the EU like to admit it or not, a large part of the UK's defence strategy is founded on the tried and tested axiom that we are stronger working with our European partners than we are going it alone. That co-operation is founded on the twin pillars of the EU and NATO, and increasingly the two are meshed into one. That approach keeps Britain more secure and gives us a stronger voice on the international stage.
Unfortunately, some in the media and in Government often play down the degree of European military co-operation the UK enjoys - for fear of cries from the Outers about dreams in Brussels of an 'EU army'. This is, of course, a fantasy designed to scare not inform. It is trotted out by those who cannot win an argument on merit and who do not understand the implications of unavoidable, mutually advantageous, defence co-operation with our neighbours.
Sadly, it has had the consequence that over the past 20 years or more, British Governments have found themselves in the uncomfortable position of pressing for closer practical military co-operation, spending more money on defence than most of our partners and neighbours, while at the same time working desperately hard to downplay the significance of what they were doing for fear of domestic misrepresentation.
But a brief roll-call of joint UK-European military exercises underlines our partnership and the many ways it contributes to the UK's security: French maritime patrol aircraft monitoring the Irish Sea for non-NATO submarines, Anglo-French co-operation on nuclear research, the hardly mentioned British-Dutch marine Amphibious Force, German tank crews receiving training in the UK, and UK participation in EU anti-piracy operations in the Horn of Africa.
Much of that co-operation had its genesis in a bi-lateral agreement signed by Tony Blair in 1998 with the French alone. But now, the whole of the EU is increasingly pooling its military and security resources and working together against threats which are almost universally common to us all.
That takes many forms: some common procurement, though it remains a challenge in many instances; shared training and maintenance; and the formation of effective combined forces, for example.
That trend has a number of advantages for the UK and other states that we would miss out on if we turned our back on Europe. First, it means that the force we present outwards to combat threats to our security is many times what it would be alone. The saying goes that two heads are better than one and in military terms it is undoubtedly true that two tanks are better than one.
Second, it creates money-saving economies and maximises the return we get from scarce resources. By training together, for example, not only do we share expertise and excellence but we get more bang for every buck invested in creating a formidable fighting force. With our Government and countries across Europe making savings in public spending wherever they can, that's an advantage whose importance cannot be understated.
Third, by working together each individual country is allowed to specialise and become a master of one trade rather than a jack of many. Then, working together, the result is many excellent capabilities rather than the same number of OK ones. For example, the RAF, in the run up to the vote on strikes against ISIS in Syria, was noted for its unparalleled excellence in carrying out precision airstrikes; the French meanwhile have the most capable marine surveillance fleet.
Finally, it means that the EU's defence strategy is co-ordinated and designed to combat the threats we all face. Because, as the 2010 Strategic Defence Spending Review spelled out, there are no security threats to Britain that we do not share with our neighbours. So it makes sense to share our military response, as far as we can without abandoning the principles of national sovereignty and accountability, with our neighbours.
The Outers balk at the possibility of British troops training with their German counterparts or - even worse - serving under foreign command. I recall Liam Fox, coming up against such a viewpoint from a Cross-Bencher in the Lords, adroitly listing off all the different NATO member states under whose rotating command British troops had served with distinction in Afghanistan. NATO, which has been the bedrock of military stability in Europe since the Cold War, is founded on the very notion of military co-operation.
So already the UK is kept more secure and has a stronger leadership role on the global stage because of our military co-operation with Europe. If we are to continue to reap these benefits though, we cannot countenance turning our back on the EU, pulling up the drawbridge and going it alone. We have to engage more widely with political elites in our partner countries to make sure that we build their support. Because it is clear that from the point of view of our national security, Britain is stronger in Europe.
Lord Wallace of Saltaire is the Lib Dem Foreign Affairs and Commonwealth