David Cameron will abandon Heathrow third runway plans, Cabinet minister declares

Her intervention, in an interview with The Telegraph ahead of this week’s Budget, risked a furious backlash and potential legal challenge from airport campaigners.

Her intervention, in an interview with The Telegraph ahead of this week’s Budget, risked a furious backlash and potential legal challenge from airport campaigners.

It came as 30 Tory MPs demanded George Osborne use his Budget to protect airports in England from higher rates of passenger tax than could apply in Wales.

Britain is running out of airport capacity in the south of England. There are fears that without a new runway serving London, flights and businesses will go to other countries in Europe in the decades ahead.

The Cabinet is still considering whether to proceed with a third runway at Heathrow, or approve a rival development at Gatwick instead.

Billions of pounds of investment and future income are at stake but but a final decision has been delayed and is not now expected until after the EU referendum in June.

Downing Street has banned ministers from making any statements on the question of where a new runway could be built, amid fears that such remarks could be used in legal action by the losing side.

But Miss Greening – a London MP and known opponent of Heathrow expansion – said she was confident that her colleagues in the Cabinet would reject the third runway plan.

“I don’t believe that this government will proceed with a third runway decision,” she told The Telegraph. “I just don’t think it is a smart decision.

“Trying to expand Heathrow is like trying to build an eight bedroom mansion on the site of a terraced house. It is a hub airport that is just simply in the wrong place.”

Miss Greening, the MP for Putney, Roehampton and Southfields, said she believed her fellow ministers would “reach the same conclusion”.

“The sooner that we can move onto working out a long term airport strategy for Britain the better,” she said.

Last autumn Sir Jeremy Heywood, the Cabinet Secretary and Britain’s most senior civil servant, warned ministers not to comment on Heathrow before an announcement amid concerns that the final decision could be vulnerable to legal challenge.

When she was Transport Secretary in the last parliament, Miss Greening said she would find it “very difficult” not to resign from the Cabinet if plans to expand Heathrow went ahead.

She has made campaigning against the third runway a key local issue in her constituency.

But she suggested that she could stay on in the Cabinet now that she no longer holds the transport brief, even if the eventual decision overHeathrow went against her wishes.

“There is no decision,” she said. “I do believe in Cabinet collective responsibility but I am in the Cabinet and I am absolutely continuing to represent my constituents’ concerns.”

Her comments came as a group of 30 Conservative MPs wrote to the Chancellor urging him to guarantee that airports in England will not be undercut by rivals in Wales.

Mr Osborne is said to be considering plans to devolve setting air passenger duty to the Welsh government.

But the group of MPs, all of whom represent constituencies in south-west England, warned that airports such as Bristol would lose business if the duty was cut at Cardiff Airport but remained unchanged in England.

In the letter to the Chancellor, the MPs, led by Liam Fox, warned that devolving APD to Wales could have an “extremely severe” impact on passengers and businesses in the region.

They predicted “more expensive travel for people in the South West when going on a hard-earned family holiday” and called on him to rule out devolving APD to Wales in the Budget on Wednesday.