Plans to reopen Manston airport could be thrown out by the government because the basis of the application will be unlawful.

Legal representatives for owners Stone Hill Park, who have plans to redevelop the site, have torn into proposals to operate the airfield as a cargo hub.

A 41-page dossier sent to the Planning Inspectorate, seen by KentOnline, claims RiverOak Strategic Partners (RSP) has made fundamental errors in its calculations of cargo movements.

These errors would render illegal its application for a development consent order, giving permission to take control of the site.

It also claims RSP “misrepresented” views on cargo from aviation consultancy York Aviation, which has since joined the Manston owners Stone Hill Park in condemning the reopening plan as a “freight fantasy”.

RSP disagreed with the assertions and said it remains confident in its work.

The dossier filed by Pinsent Masons – voted by industry experts as the nation’s top planning law firm – outlines how it believes RSP’s plans are not eligible for a development consent order and, therefore, cannot proceed any further.

It contends that RSP’s application fails to meet the criteria required because it is not able to show an increase in the cargo flight capacity of the site as an airport.

A development consent order would need to show an increase in capacity of at least 10,000 air traffic movements.

RSP claims it can deliver 17,000 cargo flights annually by its 20th year of reopening.

However, the airport’s present capacity is 21,000 cargo flights per annum.

The law firm says the application needs to be thrown out because “they have got their numbers wrong” by claiming its present capacity is zero.

Although Manston has closed, meaning it has zero flights, legally its capacity remains the same.

The dossier also says four aviation industry expert consultants have dismissed its claims of 17,000 annual cargo flights as fantasy.

Trevor Cartner, director of Stone Hill Park, said: “This compelling new legal and aviation expert advice reveals the RSP proposals to be the sham that they are.

“Even if such an airport was a realistic proposition, it would cause nightmare noise, air pollution and traffic gridlock for local residents and businesses.”

The site's owners want to build up to 2,500 homes and leisure facilities alongside a manufacturing hub which would create more than 2,000 jobs.

The Stone Hill Park site has a potential capacity for 4,000 homes.

The Planning Inspectorate said it had received the document from Pinsent Masons and will respond in due course.

A spokesman for RSP said: “RiverOak Strategic Partners disagrees with the basis on which Pinsent Mason has arrived at these conclusions.

"We are confident that all of the detailed work we and our professional advisors have undertaken for the development consent order application will clearly and robustly make the case that our proposals for Manston to meet the threshold for a nationally significant infrastructure project.”