UK orders 40 Euro-fighter Typhoon valued in £ 3 billion

It represents half the original number of jets planned for construction after Germany, Italy, Spain and Britain agreed to split the final third tranche into two parts.

Agreement has been held up by detailed negotiations involving the manufacturers, BAE Systems in the UK, and the Eurofighter programme's partner governments. The British government said those talks had secured £900 million of savings.

Of the latest batch for this country, 24 are to replace aircraft which were diverted to Saudi Arabia as part of an export deal. The first of the new aircraft, which will be based at RAF Coningsby in Lincolnshire and at RAF Leuchars in Fife, Scotland, should enter service in 2013.

BAE Systems will assemble the new jets at its existing production line at Warton in Lancashire with the engines made by Rolls-Royce in Bristol and radar supplied by Selex in Edinburgh.

The Eurofighter has been dogged by delays and cost over-runs and critics claim it is a leftover of Cold War planning and should no longer be a military priority.

After several years of speculation that Britain could axe the final tranche altogether, Prime Minister Gordon Brown announced in May that it would go ahead if a satisfactory deal could be struck with manufacturers.