Plan to share aircraft carriers with France

Britain and France are expected to reveal plans to share the use of their aircraft carriers.

This would allow Britain to scrap or downgrade one of the two replacement carriers announced in 2007 at a cost of £5.2bn, but would risk thousands of shipyard jobs.

David Cameron and President Nicolas Sarkozy are expected to announce the proposal in November.

The arrangement would ensure that one of three ships – one French, two British – remained permanently on patrol. Currently Britain's two aging vessels – HMS Ark Royal and HMS Illustrious – are occasionally both in dock at the same time.

A decision on the future of the two planned replacement carriers will be announced in the Comprehensive Spending Review in October. A shared patrolling scheme with the French military would allow one to be built to a lesser specification, sold to another country or scrapped.

The carriers would remain under the command of their respective armed forces. Discussions are under way as to what might happen should an exclusively British interest, such as the Falklands, come under attack during a period in which the French carrier was on patrol.

According to The Times, sources close to the National Security Council, the new cabinet group which decides the direction of British foreign policy, said that Defence Secretary Liam Fox was minded to give the go-ahead to both carriers, but the second may have its capability downgraded. A down-graded carrier could be used as a base for a troop landing, and take helicopters rather than jets.

However, the fast jets planned for the new British carriers would not be able to fly off the French version and French aircraft would be unable to use the British model.

Critics have already questioned the viability of such a partnership. Gwyn Prins, a research professor at the London School of Economics, told The Times: "At first glance it may seem sensible to pool aircraft carriers with the French. But a moment's reflection in the light of past history and of modern geopolitics shows why that is unwise."