UK signs deal on Joint Strike Fighter

Britain has signed up for the next phase of the US-led Joint Strike Fighter programme, after settling a dispute over technology transfers and gaining what it says will be "complete operational sovereignty" over the 150 aircraft it plans to buy.

The agreement was sealed with a memorandum of understanding signed here by Lord Drayson, the UK minister in charge of defence procurement and Gordon England, the US deputy Defense Secretary.

The deal came days before the JSF, or F-35, is to make its maiden flight in Texas - the next step in the Pentagon's biggest ever procurement programme, with an estimated total price of $275bn (£140bn). Britain has put over £600m into the demonstration and development phase. Yesterday's move means it will be committing a further £34m to the initial production of the stealth multi-role plane.

Britain is Washington's most important partner in the JSF, which will be the backbone of the airforces of the US and the eight other participating countries. But just last week it was talking of pulling out, and adopting a "Plan B" if the US did not make available the software codes and other technology required to operate the plane independently.

Lord Drayson said he had been assured "within the last 24 hours" that the Pentagon would allow an unbroken British chain of command once the planes were in service with the Royal Air Force. "It will not be a requirement, for example, to have US Air Force personnel on a British aircraft carrier to deliver our operational sovereignty." Only on Friday, a report by the Parliamentary Defence Committee said it was "still uncertain" that the US would hand over sensitive information - and even yesterday Lord Drayson said Britain had not ruled out a back-up plan, which could involve a carrier-capable version of the Boeing F-18 Super Hornet, Marcel Dassault's Rafale, or the Eurofighter Typhoon.