CONCERNS have been raised about the viability of a proposed airport in the Thames Estuary.

London mayor Boris Johnson wants to look at the possibility of the new airport instead of expansion at Heathrow.

But Southend Council leader Nigel Holdcroft said: “There is no harm in having a debate about it and we would be happy to take part when more details emerge.

“However, I personally think it is really a non starter, simply because of the massive costs involved.”

Mark Willingale of Metrotidal, the firm behind plans for a Lower Thames Crossing – a tunnel between Canvey and Kent, said: “The debate is open and we are looking closely at what is coming.”

Mr Willingale, who was also connected with the planned Thames Reach Airport in Cliffe, Kent, said: “I can see a number of problems with the proposal, not least of which is the transport situation.

“It has been suggested there could be a ferry across the Thames from Essex to the airport, but I can’t really see that being feasible.

“One of the most important things we need in the Thames Estuary is substantial improvements in the infrastructure.”

The preferred site for the proposed four-runway airport would be off the Isle of Sheppey in Kent, which is opposite Southend seafront.

The site was picked rather than Maplin Sands off Foulness Island, which was favoured by Edward Heath’s Conservative Government in the Seventies.

A spokesman for Mr Johnson said: “The mayor wants to undertake a study to establish the feasibility of the idea once and for all and is examining the best way to take the study forward.”