These firms and others across the country can now look forward to up to �24bn worth of work, including �3bn in the initial development phase of the Joint Strike Fighter (JSF).

UK firms to benefit

BAE Systems plants in Lancashire and Kent Smiths Industries in Wolverhampton Rolls-Royce in Bristol TRW Lucas in Solihull Ultra Electronics in Cheltenham ARA in Bedford

The contract represents the biggest defence order ever, with the United States armed forces ordering more than 3,000 of the aircraft.

BAe System's chief executive John Weston said the contract would both create and safeguard thousands of jobs throughout the UK and the US.

There is also to be many more indirect jobs with sub-contractor companies.

Trade and Industry Secretary Patricia Hewitt said it was "excellent news" for the British aerospace industry amid testing times.

She said: "It proves that British companies can compete with the best in the world for the big contracts."

'Ray of hope'

Union leaders in the UK also welcomed the announcement.

Roger Lyons general secretary of the Manufacturing Science and Finance Union, said: "This brings a ray of hope for the troubled aerospace industry.

"Thousand of UK jobs will be secured which is great news and will offset some of the damage which has hit the sector since the US terrorist attacks".

Part of the BAe prototype is made in Lancashire

Ahead of Friday's announcement, American aerospace journalist, Alison Gatlin, said the stakes were very high.

"It is the biggest procurement contract ever and probably until at least 2030.

"So because they're saying it's going to be a winner-takes-all kind of contract, the company that loses could conceivably be out of the fighter business."

Test flights

Part of the Lockheed prototype, known as the X35, is made at BAe in Salmesbury, Lancashire.

In a unique example of trans-atlantic co-operation, BAe test pilots have been flying the fighter alongside their US colleagues.

This brings a ray of hope for the troubled aerospace industry.

Roger Lyons, Manufacturing Science and Finance Union

One of these British pilots, Simon Hargreaves, is based at the BAe plant at Warton, near Preston.

"As a prototype, it is quite representative of the production aeroplane," he said.

"But of course it isn't as developed as the production aeroplane will be. Flying it was fascinating and challenging.

"Ultimately, it was very successful and a very rewarding 18 months of my life."

Mr Hargreaves has been particularly involved with the vertical take-off version at Lockheed's site at Palmdale in the Californian desert.

He used to fly harriers, including service in the Falklands, but says the JSF is a very different aircraft.

"It is important to know that the X35 is about twice the weight of a harrier, and has rather more than twice the thrust, so it's a different class of aeroplane.

"And in addition, its tactical performance far surpasses that of the other and it's got lots of other clever features. It's a different class of aeroplane."