The Eurofighter has taken more than 20 years to design and build

Britain is estimated to have spent more than �19bn on the aircraft, which was expected to cost �16.7bn and has been dogged by delays.

Critics say the jets are no longer relevant to today's defence needs, but Defence Minister Lord Bach says they will be a real asset to the country.

The RAF unveiled the aircraft at RAF Coningsby, in Lincolnshire, on Friday.

The Eurofighter, or Typhoon as it is known in the UK, has been developed by a consortium of British, German, Spanish and Italian companies.

It is immensely powerful, which means it can fly very fast, very high and turns extremely well Flight Lt Antony Parkinson 29 Squadron

Aircraft from the original 1998 order of 55 are currently being tested at defence firm BAE Systems' site in Warton, Lancashire.

The government says it plans to buy a total of 232 Eurofighter planes.

Chief of Air Staff, Air Marshal Sir Jock Stirrup, said: "We now have an outstanding combat aircraft that, with its multi-role capability, flexibility and adaptability, gives us the ideal basis on which to meet the challenges of an uncertain future."

And Defence Secretary Geoff Hoon said: "This is all about equipping our armed services with the best technology and the best equipment to allow them to carry out their duties."

Mr Hoon, who said the latest order will safeguard about 16,000 jobs, added: "We are demonstrating a long-term commitment to this aircraft and the RAF."

It has taken over 20 years to develop the plane, and critics have attacked the spiralling budget, as well as the project's timescale.

Rising costs

RAF pilot Antony Parkinson, who has flown the plane for the last two months, said the Eurofighter was "a delight to fly".

Flight Lt Parkinson, of 29 Squadron, said: "It is immensely powerful, which means it can fly very fast, very high and turns extremely well at all altitudes."

As a customer, the RAF is delighted with it Air Chief Marshal Sir Brian Burridge

David Mulholland, business editor of Jane's Defence Weekly magazine, said the project delays were partly due to the fact the Eurofighter was originally "designed to counter Soviet aircraft".

The requirements of the plane changed as this was "no longer a threat", with the emphasis shifting to a need for jets to hit targets on the ground, he added.

Defence analyst Paul Beaver told BBC News the rising costs were largely down to the plane's electronic systems and the RAF's need for it to have "precision bombing" and "ground attack" capabilities.

Problems corrected

A dispute in Germany over its share of the funding further delayed production.

The manufacturers have also had to address claims the jet underperformed in trials, particularly with regard to dogfight manoeuvrability.

Qinetiq, the MoD's privatised research agency, said technical problems its assessors highlighted in May, had been corrected.

In August this year, Britain's most senior airman, Air Chief Marshal Sir Brian Burridge, insisted the Eurofighter was an "amazing aircraft".

"As a customer, the RAF is delighted with it," he said.

Germany is buying 180 of the jets, Italy 121 and Spain 87.