Backers of an alternative Heathrow expansion scheme have repeated a demand for government to review the airport’s third runway plans.

Heathrow Hub claims two “significant changes in circumstances” – spiralling costs and the incompatibility of the third runway with the government’s net zero carbon emissions target by 2050 – merit a new probe.

It is demanding action from prime minister Boris Johnson – a long time critic of Heathrow expansion –  and transport secretary Grant Shapps.

Heathrow Hub has appealed the High Court’s refusal to quash the Airports National Policy Statement and is awaiting a judgement from the Court of Appeal.

Jock Lowe, director at Heathrow Hub, said: “The government should stop prevaricating and review this unnecessarily expensive and disruptive option for Heathrow expansion and instead choose our cheaper, greener, quieter, quicker and simpler scheme, which will ensure that environmental standards are met, not compromised.

“The complexity of the project and its associated costs continue to balloon, affecting airlines, consumers and local communities who will suffer as a result of increased costs, noise and emissions.

“Our extended runway can still, even now, be built before the third runway.

“It is a solution that has been deemed viable by the Airports Commission and it will cost just £4.7 billion for the first phase.

“It does not rely on extra flights. It will make the airport more efficient. It will ensure passenger charges stay flat. And it is a way out for Boris Johnson, who rightly does not like the third runway.”