American carriers, pressing for more slots at Heathrow, would be given new routes from Manchester to Los Angeles and from Stansted via New York to Chicago.
A spokesman for the Department of Transport said he hoped the offer would be seen as a sign of willingness from the Government. However, UK airlines felt it would have little effect on the US carriers' determination for better access to Heathrow, the world's busiest airport and seen by US passengers as the gateway to Europe.
The current Anglo-US bilateral agreement allows only American Airlines and United Airlines to serve Heathrow. The US pulled out of talks about greater access, in part because the conflicting interests of American carriers made it difficult for US negotiators to present a united case.
In April Richard Branson's Virgin Airlines signed a marketing partnership with Delta Airlines. The American company would block-buy up to pounds 100m worth of seats on Virgin flights each year, giving it access to Heathrow. The deal, approved in the UK but not yet in the US, was seen then as a lever to encourage the Americans to re-start talks.
There was speculation yesterday that the routes offer would do more to help Virgin receive US approval than it would to start the bilateral talks.
John MacGregor, the Secretary of State for Transport, said: 'I am making this offer in order to maintain services for consumers while we continue to seek to make progress in securing a wider liberalisation of UK-US air services. This further move from the UK should provide another demonstration to the US of my determination to secure liberal changes to the current air services agreement.'
American Airlines withdrew from the Stansted-Chicago route last year and British Airways will suspend its Manchester-Los Angeles service in the autumn, an indication that neither route is profitable nor likely to be attractive to other carriers.