WORK has started on the next generation of supersonic aircraft at BAE Systems' Samlesbury site, near Preston.

The aerospace giant will build the aft fuselage, and the tail, for the F-35 Joint Strike Fighter (JSF) which is being built in co-operation with the United States of America.

More than 400 employees at the Samlesbury site are working on the project to build 21 development aircraft, in a contract worth £1.1billion to BAE. Work at the state-of-the-art facilities started last week to attach the fuel tank into the keel of the new aircraft.

The JSF will be built in three variants, to suit the different needs of separate armed forces.

One will be a conventional take off aircraft, the second will have short take off model with vertical landing capabilities, and the third type is being developed for Navy aircraft carrier take off and landing.

Programming director Michael Christie, said: "This milestone marks the start of an assembly process which, during the summer of 2005, will see BAE Systems JSF team delivering not only the aft fuselage but also the horizontal and vertical tails of the first aircraft."

The development phase to build the JSF is of massive importance to BAE as more than 2,500 of the aircraft will eventually be required.

The JSF is set to replace the A-10, the Harrier, the F-16 and F/A-18 aircraft in current service in both Britain and the USA.

Frank Hayden, site director at Samlesbury, added: "Samlesbury has a distinguished history in the production of world class aircraft and we are delighted to add JSF to that prestigious list.

"Achieving today's milestone is great news for the Samlesbury team and all our suppliers."