A key group of MPs has rejected the idea of an international airport in the Thames estuary.

Instead the transport select committee says Heathrow should build a third runway - and even a fourth one.

The committee has spent months examining Britain’s air capacity ahead of an official inquiry, the Davies Commission, which will only report in 2015.

But its shock report, out today, will put pressure on the government to reject an estuary hub.

Medway Council leader Rodney Chambers (Con) is celebrating.

Once again he said the plan was “pie-in-the-sky”, adding: “This confirms what we’ve always known, and have campaigned loudly about.”

Influential people have put forward plans for the estuary, including renowned architect Lord Foster and former Cathay Pacific executive John Olsen.

They see it as prime development land, to the fury of environmentalists and those who believe it will only benefit London.

But the select committee’s report said an estuary hub was not viable for three reasons: cost, environmental damage and the need to close Heathrow.

“Building an entirely new hub airport east of London could not be done without huge public investment in new ground transport infrastructure,” said committee chairman Louise Ellman.

Related article: London Assembly says estuary airport 'not needed'

Closing Heathrow, on the other hand, “would have unacceptable consequences for individuals, businesses in the vicinity of the existing airport and the local economy.”

The shock report suggests not just a third but a fourth runway around Heathrow - an idea which will horrify the Tory heartlands of the M4 corridor.

It also urges Gatwick, which cannot expand until 2019, to start preparing a business case.

But it dismisses the idea of a high-speed train connecting Heathrow and Gatwick, saying transfer times would still be too slow.

The report also calls on the government to:

• Establish a national compensation scheme for those affected by Heathrow’s expansion.
• Improve road and rail access to the UK’s current airports.
• Have High Speed 2 call at Heathrow and introduce direct lines to Gatwick and Stansted.
• Promote the better use of airports outside the south east.
• Commission a study which could lead to the axe or reduction of air passenger duty.

Speaking earlier this year, Mr Olsen said his airport plan at Cliffe could save north Kent.

"Do you want malnourished and ill-educated children growing up?" he said. "Here is a project that will really help these people.

But Rochester and Strood MP Mark Reckless said the report “drives a coach and horses” through those plans.

“It is a huge boost for those of us opposed,” he said. “However, it is important that we stay focused on our ultimate goal of killing off these pie in the sky proposals once and for all.”