Britain is reported to have signalled that it will not block a landmark EU deal with the US to open transatlantic flights to greater competition.
The Reuters news agency quoted diplomats as saying that Britain had given the indication at an ambassadors' meeting on Monday.
It appears that Britain will not obstruct the 'open skies' agreement when EU transport ministers meet to approve it on Thursday but will seek a delay in implementing it at London's Heathrow Airport.
Britain also wants an EU commitment to automatically withdraw concessions made under the pact if the US does not agree by mid-2010 to allow European airlines to buy control of US carriers, the diplomats said.
The 'open skies' deal is seen as crucial to Aer Lingus's future plans as it wants to expand its long-haul services in the US.