Lockheed Martin beat competition from Sikorsky, which has built Marine One helicopters for about 50 years.

Victory for the Anglo-Italian design is expected to help Lockheed's bids for up to $6bn in upcoming defence contracts.

A US Air Force contract for up to 194 top-of-the-range helicopters is expected to be negotiated in 2006.

And the US Coast Guard and Department of Homeland Security are reported to be searching for a supplier for about 200 helicopters.

National pride

The current presidential fleet of ageing Sikorsky VH-3D helicopters will be replaced by Lockheed's high-tech, high security US101 model.

The interiors of the helicopters will be furnished in presidential style
The Lockheed bid, designed by AgustaWestland, was backed by UK Prime Minister Tony Blair and Italian leader Silvio Berlusconi, both supporters of the US-led military campaign in Iraq.

Lord (William) Bach, the UK's Minister for Defence Procurement, welcomed AgustaWestland's win.

He said: "I am delighted that the US authorities have selected the US101 as the best helicopter to meet this important requirement, after a long and strongly contested competition.

"This is good news for the UK and AgustaWestland. It will sustain and enhance vital leading edge helicopter design capabilities in the UK." About two-thirds of the new helicopter will be built in the US, with the remaining production split between the UK and Italy.

The contract will provide a boost for Westland's factory in Yeovil, Somerset, where the blades of the US101 will be built.

The Pentagon insists it routinely favours the best defence technology without allowing national considerations to cloud technical judgement.

Lockheed is already a major defence contractor for the Pentagon.

But throughout the bidding process Sikorsky stressed its US roots, citing security and patriotism concerns among the company's strengths.

"We have a personal staff dedicated to maintenance, and you definitely need an American staff to handle such security requirements," Ed Stedham of United Technologies said.

Lockheed spokesman Mike Drake denied his firm's product would be a European product: "The helicopters will be built in Texas and customised in New York and maintained in the US," he said.