WORKERS at BAE Systems in Samlesbury have reached a milestone in the multi-billion-pound contract to produce the next generation of supersonic fighter plane.

Assembly work has now begun on the rear fuselage of the Joint Strike Fighter on which the jobs of thousands of East Lancashire aerospace workers will depend for the next 20 years.

In the world's biggest-ever defence contract, the JSF is being developed for the US Air Force, Navy and Marine Corps, as well as the UK's RAF and Royal Navy.

Around 500 BAE staff at Samlesbury are working on the jet fighter, building the rear fuselage and the horizontal and tail wings.

Numbers will rise to more than 2,000 as the plane moves from the development phase.

Michael Christie, programme director at BAE, said: "One of the skills that BAE Systems has brought to the JSF programme is advanced assembly techniques and processes, many of which have been developed at Samlesbury.

"On JSF, we are now taking those to another level."

Vice-president Tom Fillingham said the start of assembly was a major step forward for BAE and the whole of the UK aerospace industry. "When you consider that the current requirement for JSF is in excess of 2,500 aircraft, it emphasises the importance of this day for all involved," he said.

"BAE's involvement on the JSF programme will help maintain vital design, engineering and manufacturing skills, not only within BAE Systems, but across the UK as a whole."

The JSF will set new standards for assembly precision and pace. New milling machines are accurate to within 50 microns -- about one-third the width of a human hair -- to ensure that the JSF's outer shape is exact and meets its stealth requirements.

During full-rate production, assembly time for the JSF is expected to be less than half that of current-generation fighters.

And, in a historic week for BAE, the new Nimrod completed its maiden flight from Woodford, in Cheshire, to Warton where workers have been working on the plane for the past seven years. The maritime reconnaissance plane, four years behind schedule and hundreds of millions of pounds over budget, is due to enter service with the RAF in 2009.