'New era' for Anglo-French forces
David Cameron and President Nicolas Sarkozy will usher in a new era of Anglo-French defence co-operation which will see the two countries pool troops, aircraft carriers and nuclear testing facilities.
At the Anglo-French summit in London, the two leaders will sign far-reaching treaties which will commit their forces to operating together for decades to come.
Downing Street said that defence co-operation with France was based on a "hard-headed and practical assessment" of the UK's national interest.
"This summit marks a deepening of the UK-France bilateral relationship. Ours is now a strategic partnership tackling together the biggest challenges facing our two countries," a No 10 spokesman said.
The agreement will also see the two countries pooling resources in terms of training, maintenance and logistics for the new A400M transport aircraft which they are both acquiring, while French fighter jets could be re-fuelled in flight from British tanker aircraft.
In the longer term, the two countries will work together on a whole range of programmes including satellite communications, cyber security and the development of new missile systems, submarine technologies and unmanned aerial drones.
The move comes as both nations - long seen as the major European military powers - are looking to cut the cost of their armed forces.
Publishing the Strategic Defence and Security Review (SDSR) two weeks ago, Mr Cameron announced that the defence budget was to be slashed by 8% over the next four years as the Government tackles the deficit.
It was acknowledged in Whitehall that achieving better value for money is one of the key aims of the Anglo-French agreement on both sides of the Channel.
While the prospect of greater co-operation with the French was raised by the former Labour government in a defence Green Paper last year, the new agreement was said to reflect the personal engagement of the Prime Minister and Mr Sarkozy.