Nearly a third of the Royal Navy fleet is positioned off the coast of France today for a major exercise with the French military.
Six British ships and 3,000 UK military personnel are taking part in Exercise Corsican Lion to develop the joint naval force being set up by Britain and France.
The two countries are creating a ready-made task group which can react at short notice to events anywhere in the world.
The Defence Secretary, Philip Hammond, and the Chief of the Defence Staff, General Sir David Richards, have flown to the Mediterranean to inspect the force.
Mr Hammond says the joint Task Group will "ensure that the Royal Navy can respond to, and deal with, emerging events around the world."
He stresses the joint operation with "our French allies is in both our interests."
The joint operation is the result of a major agreement signed in 2010 as both countries come to terms with their own tight defence budgets which will limit what each can achieve militarily on its own.
The Royal Navy, currently operating without an aircraft carrier, has sailors on board the French carrier Charles de Gaulle.
Britain will not have a carrier in its fleet until it takes delivery of the Queen Elizabeth, currently under construction in Scotland.
She will not start sea trials until 2017 and won't become operational before 2020.
The Ministry of Defence is building a second aircraft carrier, the Prince of Wales, but the Government will not decide until 2015 whether it will be sold, mothballed or put to work.
Exercise Corsican Lion is being led by the Royal Navy's flagship HMS Bulwark.
Reporters travelling with the Defence Secretary have been told there is "no time" to film him when he visits the French aircraft carrier.
But the exercise is a major advance for Anglo-French relations since the Battle of Waterloo - when the British defeated Napolean in 1815.
And Royal Navy sources also admit many in the French Navy have not forgotten a decision by Winston Churchill in 1940 to sink the French fleet off the Algerian coast to prevent it falling into Nazi hands. More than 1200 French personnel were killed.