London Mayor Boris Johnson has attacked MPs for 'unfairly' dismissing his plans to build a four-runway airport hub in the Thames Estuary.
Mr Johnson was responding to the findings of an influential House of Commons committee that said the idea should be ditched in favour of a third runway at Heathrow.
A report published today by the House of Commons Transport Committee warned that the plans for a so-called 'Boris-Island' would be hugely expensive, could harm estuary wildlife and may mean the closure of Heathrow.
Instead MPs said an extra runway at Heathrow was necessary and also suggested that a fourth might have merit if the two new runways were located to the west of the current site. The current two-runway airport was "not adequate for the needs of the UK" and expansion of Heathrow was "long overdue", they said.
Speaking this morning the Mayor responded by saying that a third runway would be "obsolete" by the time it was built, and that the report made plain that advocates of this solution were effectively calling for a four-runway Heathrow, which he said would be "environmentally and politically undeliverable".
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."
He said the estuary airport plan 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."
Mr Johnson also said that plans to expand Heathrow would be too expensive joking that: "It would probably be cheaper to move London slightly to the east."
Chair of the transport committee, Louise Ellman said: "We recognise that demand for air travel across the UK is forecast to grow, believe that aviation should be permitted to expand and accept that more capacity is necessary to accommodate sustainable aviation growth.
"We looked closely at the three main options by which the UK could increase its hub airport capacity. Research we commissioned made plain that building an entirely new hub airport east of London could not be done without huge public investment in new ground transport infrastructure.
"Evidence to our inquiry also showed a substantial potential impact on wildlife habitat in the Thames Estuary."
Mrs Ellman continued: "The viability of an estuary hub airport would also require the closure of Heathrow - a course of action that would have unacceptable consequences for individuals, businesses in the vicinity of the existing airport and the local economy.
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."
Video: MPs back Heathrow expansion