Mayor defends 'Boris Island' Thames Estuary airport plan

The report, published as the Davies Commission continues its investigation into airport capacity in the south-east, also called on the Government to establish a national scheme to ensure adequate compensation for people affected by noise from expansion at Heathrow.

But Mr Johnson said that more runways at Heathrow would inflict environmental harm on Londoners living around the airport, while the cost of a fourth runway was "unquantifiable" and relocating runways to the west of the airport's current location would require a "colossal" amount of new transport infrastructure.

"It would probably be cheaper to move London slightly to the east," he joked.

The Mayor told BBC Radio 4's Today programme: "The crucial thing is that the third runway, even if it were to be built by 2028, would be immediately obsolete, because there would be overwhelming demand, as Louise and the committee in this report rightly prefigure.

"There would be overwhelming demand for a fourth runway. The cost of that whole project is completely unquantifiable. Nobody knows how much it would cost. The environmental damage to London is very, very considerable."

Mr Johnson insisted that the estuary airport was "a long-term solution" to London's aviation needs and the environmental impact on birds in the area could be "mitigated".

"The trouble with a third runway is it just compounds the mistake," he said. "What the Transport Select Committee have revealed in their call for a four-runway hub airport is that the Heathrow-ites are really intending to build a four-runway airport in the west of London, which in my view would be environmentally and politically undeliverable."

Today's report also urged the Government to ensure that the planned HS2 high-speed rail line rail network serves Heathrow.

And the MPs called for a study of how far the Air Passenger Duty airport departure tax impacts on the UK economy, warning that the levy should be significantly reduced or abolished if this study provides clear evidence that it is harming the economy or Government revenues.

An APD "tax holiday" should be introduced for a 12-month trial period for new services operating from airports outside south-east England, they argued.

The MPs' report said it was "immensely disappointing" that a decade after the publication of the 2003 aviation white paper and the previous Labour government's decision to support a third runway at Heathrow, the UK was still faced with an unresolved problem of aviation capacity.

"Following decades of policy papers, inquiries, taskforces, and commissions, it is the lack of a long-term cross-party political strategy for aviation that is principally to blame for the very real danger that the UK could lose its status as an international hub for aviation," said the committee.

"The current situation is unsustainable. A two-runway hub airport (Heathrow) is not adequate for the needs of the UK. We have considered the options put to us and on the basis of the evidence we have heard we recommend that the Government allow Heathrow to expand.

"Heathrow is the jewel in the crown of international aviation and we believe that a third runway is long overdue. British businesses are overwhelmingly in favour of this option."

The report said it was "less than ideal" that the Airports Commission inquiry, chaired by Sir Howard Davies, was working to "a protracted timetable, with a final report not to be produced until after the 2015 general election".

The committee continued: "We could complain that this is yet another example of important decisions on aviation being kicked into the long grass, but instead we challenge the Commission to use this opportunity to, once and for all, provide a robust and independent evidence base for future decisions.

"It is our hope that the Commission will produce an evidence base that is widely accepted across the political spectrum, and clear recommendations for action.

"The challenge for the post-2015 Government will be to quickly get to grips with the recommendations of the Commission and not seek excuses for further delay."

Shadow transport secretary Maria Eagle said: "The lack of consensus on airport capacity in London and south-east England is precisely why Labour first proposed the independent Airports Commission.

"Since David Cameron has asked Sir Howard Davies not to deliver his final report until 2015, it will be for the next government to decide on the way forward.

"In the meantime, it is right to allow the Commission to consider all the arguments and evidence presented to it without the political parties pre-empting its conclusions and recommendations."

A Department for Transport spokesman said: "This Government is determined to find a lasting solution to maintain the UK's global aviation hub status.

"The strength and range of opinions expressed on the issue shows precisely why we are right to ask Sir Howard Davies to conduct a detailed, independent review of all the options, based on the most up-to-date information."

He went on: "Previous attempts to tackle the question of airport capacity have failed, often due to a lack of consensus on the evidence. Our approach is to build a strong political consensus so we can plan for the future."