BUILDING an airport at Cliffe could cost a massive £3billion more than first thought and it might not be able to open until 2018 at the earliest – seven years later than forecast.

The damning conclusions form part of a report commissioned by Kent County Council which casts serious doubt on the practicality of the Cliffe option.

Consultants say there are flaws in virtually every assumption the Government has made about the case for Cliffe which dramatically undermines the argument for it.

Their 27-page initial draft report, which will form the basis of KCC’s official response to the Government, is highly critical of the Government’s own consultation paper.

Among the report’s main conclusions are that:

* The costs of an airport at Cliffe have been “grossly under-estimated” and could be more than £16billion

* A town the size of Maidstone would have to be built to accommodate the 59,000 new homes needed

* Up to 181,000 new jobs could be created by 2030 – 70,000 more than suggested

* Up to 109,000 houses could have to be built instead of the 23,800 indicated – swallowing up large parts of Green Belt land

* The airport could not practically be built and open for business before 2018 at the earliest and possibly as late as 2025

* A railway station the size of Charing Cross would be needed to serve the airport

Council leaders believe the independent findings, produced by respected international transport consultants Mott McDonald ought to be enough to persuade ministers that the Cliffe option should be abandoned.

Sandy Bruce-Lockhart, KCC’s Conservative leader, said: “The case against Cliffe is even stronger than we first thought it was. The fact that they are suggesting the costs could be £3billion more is remarkable; as is the suggestion of the length of time needed to build it. That would be a disaster for Kent, with possibly 16 years of blight.”

KCC would be pressing the Government to remove the Cliffe proposal in any subsequent White Paper, he added. “It cannot be a serious contender and therefore we would want to see it dropped as a proposal as soon after this initial consultation period ends,” he said.

Consultants say the costs have been under-estimated partly because the Government has failed to include the bill for building a second Lower Thames Crossing (£700million) and the omission of any sum for road and rail costs – estimated at £200million.

A further £400million would be needed for air side road and cargo tunnels and baggage handling.

As a result, consultants believe Cliffe “represents significantly worse value than other options…costing 50 per cent more than others.”

On the issue of when the airport could open, the report demolishes the Government’s timetable saying that a date of 2011 is “totally unrealistic.”

This is because the Government has not included the time it could take to establish new wetland habitats to compensate for the loss of protected sites. According to experts, this is a process which could take ten years.

KCC will argue that the solution to increased passenger demand in the south east lies in providing extra capacity in phases at Heathrow, Gatwick, Stansted and Luton.

It believes an additional runway at Gatwick could cope with 15million more passengers and a second runway at Stansted could cope with 47million more travellers a year.