An area larger than Disneyland in Paris would need to be found to house the hundreds of thousands of birds relocated to make way for a Thames Estuary aiport.

That is the claim as new evidence is revealed that appears to shoot down any hopes London Mayor Boris Johnson now has of building a massive airport hub on the Isle of Grain.

A new study reveals at least 3,400 hectares - or one-and-half- Euro Disneys - would be need to replace habitat lost to build the so-called Boris Island.

Mr Johnson has admitted finding a new home for the masses of wildlife is the development's biggest challenge.

Last week we revealed the cost of moving the wildlife could reach £2 billion.

But new research from the British Trust for Ornithology says a huge area would be needed to re-home the 300,000 birds affected by building the huge airport.

The report says: "Coastal wetland habitat loss of this type has been widely demonstrated to have significant impacts on the bird populations that the habitat supports.

"We can therefore be confident that habitat loss due to airport development would have significant negative impacts on the bird population that depend on the areas lost."

The architects behind the proposed airport, Foster and Partners, predict it could cost up to half a billion pounds, but a report by the government's Airport's Commission estimates it could be anything up to £2 billion.

MP for Gillingham and Rainham, Rehman Chishti, said: "This report clearly shows the high risks, uncertainty and costs of putting an airport into an area which is one of the most important for waterbirds in the UK."

"It would decimate these important environmental areas with any mitigation or compensation measures requiring vast areas of land to be made available at enormous cost.

"This is another showstopper report demonstrating why this absurd scheme should never be allowed to go ahead."

Cllr Rodney Chambers, leader of Medway council, dubbed the latest report "another stumbling block in these Mickey Mouse plans."

He said creating a new habitat away from the Medway Estuary is likely to lead to a higher death rate among the birds, would take years to establish and might not even be legal.

The news comes as Kent County Council has back-tracked over its support for a new runway at Gatwick to address increased demand for aviation capacity in the south east.

County transport chiefs say the council would now support expansion at either Gatwick or Heathrow - but have reaffirmed KCC’s opposition to a new Thames Gateway airport.

The change is detailed in a new KCC blueprint “Facing The Aviation Challenge.”

The report has been drawn up to take into account the interim findings of the government’s aviation commission, headed by Sir Howard Davies.

Although KCC has not ruled out backing expansion at Gatwick it now states that it “gives support in principle to expansion at either airport as the right solution to other UK’s aviation needs.”

"This is another showstopper report demonstrating why this absurd scheme should never be allowed to go ahead" - Rehman Chishti MP

The original document sparked a backlash, with the Tonbridge and Malling MP Sir John Stanley particularly critical of the policy on Gatwick.

At the time, he said the backing for Gatwick was “quite extraordinary.”

On Manston, KCC says “a financially viable and sustainable future must be found” which include using it for “aviation related services.”

On a possible new runway for Gatwick or Heathrow, it says both would be built more quickly than a new hub airport in north Kent and would cost significantly less.

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