Justine Greening could become the first Cabinet Minister to be removed from her job because she supports Government policy, it was suggested yesterday.
Some senior Conservatives, who are in favour of building a third runway at Heathrow to boost economic growth, said that Ms Greening's long-held opposition to the plan meant that she could not remain in her position as Transport Secretary.
They suggested that with Chancellor George Osborne now in favour of a third runway it would be necessary to move Ms Greening in the planned September reshuffle to allow a U-turn to take place. However, others in Government dismissed the idea, pointing out that opposing the runway was Government policy.
They added that the Liberal Democrats had been clear that they would block the move and that David Cameron said last month that Government policy would not be changing. But Richard Wellings, head of transport at the Institute of Economic Affairs think-tank, said Ms Greening's position was "untenable".
"It is a problem having her as Transport Secretary with such a local interest in the issue; given her critical views on Heathrow expansion, it would make sense to replace her," Mr Wellings told the Financial Times.
One senior Tory added: "It would be bizarre to keep her in that job when her position over aviation is now the polar opposite of the Prime Minister and the Chancellor."
The Government is expected to publish its long-awaited consultation into airport expansion in the South-east in the next couple of months. While that will not specifically rule out a third runway – and ask for supporters to make a case for it – it will make clear that Government policy is to look for other solutions.
Willie Walsh, chief executive of International Airlines Group, which controls British Airways, said he saw the lack of progress on aviation as a "disgrace".
"I don't believe this government has the political will to address the issues," he said. "David Cameron seems a lot happier clapping and cheering for gold medals than dealing with tough, long-term economic challenges."
Ms Greening made her name campaigning as a backbencher in her Putney constituency through her resistance to a third runway at the airport. The Tories entered the 2010 general election opposing the Heathrow scheme, but many MPs now want a public U-turn on the issue to promote economic growth.
Richard Harrington, a Tory backbencher, said he backed "anything that will increase capacity" at Heathrow.
"I was very impressed at Justine Greening at the Treasury and I'm sure that if she had a problem with the Heathrow project they can put her in another more senior job where her talents could be properly used by the Government," he said.
But Department of Transport sources pointed to remarks made by Mr Cameron just last month, in which he effectively ruled out a third runway – at least in the short term.
"Be in no doubt, by the end of the year we will have both this review underway and the call for evidence about all the future options underway, and I think that's vitally important," Mr Cameron said.
He added: "Both the Coalition parties made a pledge not to have a third runway, and that's a pledge that we made and that we will keep."