Flybe’s interest in opening up a west London RAF base to UK regional flights has won the backing of capacity-constrained Heathrow.
The west London hub believes the use of RAF Northolt would act as stop-gap measure ahead of any proposed third runway.
The development emerged as David Cameron was urged to delay a decision on giving the green light to the expansion of Heathrow until the airport shows it can meet air pollution targets.
MPs on the Commons environmental audit committee called on the prime minister to put off his backing until Heathrow can prove that increased capacity will not lead to deteriorating air quality.
A new runway at Heathrow over a second runway at rival Gatwick was recommended for government approval by the Airports Commission in July, with Cameron pledging to give a decision before Christmas.
A report by the committee calls on the government to outline “concrete proposals” to deal with the environmental issues, suggesting that a further consultation period on the already drawn out decision-making process could be needed.
The Times reported committee chairman and Labour MP Huw Irranca-Davies as saying: “To defer dealing with the environmental impact of a third runway would be irresponsible and could lead to legal challenges as a result of the potential damage to public health from increased air pollution and noise.
“If the government decides to accept the recommendation for a third runway in principles, we will seek assurances from the secretary of state for transport that environmental conditions will be met before it is given final approval.”
Gatwick Airport chief executive, Stewart Wingate, said: “This is a highly significant intervention by the environmental audit committee just days before the government is expected to make its decision on airport expansion.
“The committee questions the entire legal basis of the Airports Commission report on air quality and highlights the many other environmental hurdles facing Heathrow expansion.
“It is increasingly clear only expansion at Gatwick is legal and can actually happen.”
His comments came after Gatwick attacked Heathrow’s plans for spending £180 million to double cargo volumes, claiming this would also worsen air pollution – an assertion dismissed as “entirely spurious” by the west London hub.
Responding to the environmental audit committee’s report, Heathrow environment and sustainability director, Matt Gorman, claimed that its plan has the potential to create a cleaner and quieter airport that takes advantage of greater public transport use and sustainable design.
“The committee is absolutely right that the environmental impact of a third runway must be considered alongside the economic benefits expansion will bring,” he said.
“Our new plan for expansion has ensured that Heathrow will be quieter, public transport to the airport will be transformed and air quality will continue to be improved and limits will be met.
“We have committed to significantly increase the amount of time each night without any scheduled flights but believe the start and finish time of a night flight ban should be decided by government through consultation, which must include the local community.”
The latest row over the environmental impact of an expanded Heathrow – expected to win the support of a dedicated Cabinet sub-committee – came as Heathrow welcomed the use of RAF Northolt, 10 miles away, as a short term measure for providing regional connectivity.
“After a £20 million two and half year study, the Airports Commission unanimously found that Heathrow needs to expand,” a Heathrow spokesman said.
“Using Northolt would be an interim solution to the capacity constraints at Heathrow which have existed for over a decade.
“The fact that Flybe want to bring more UK passengers to Heathrow is a vote of confidence in the hub model and in the strength of domestic demand.
“We are committed to improving domestic connectivity at the UK’s hub and we want airlines like Flybe to fly straight into an expanded Heathrow.”
Heathrow previously voiced its willingness to work with airlines that wish to operate UK domestic flights to RAF Northolt in response to the National Connectivity Task Force last year.
It suggested supporting the creation of an executive coach service to provide landside to landside links for passengers connecting between flights at the two airports.