Manston Airport is set to close with the loss of nearly 150 jobs, it has been announced today.

The owners of the airfield - which dates back to the First World War - confirmed the move in a statement today as no "viable alternative" to closure had been found.

Unless a credible buyer is found at the 11th hour, the airport will shut for the final time on May 15.

In a statement this morning, a spokesperson for Manston Airport said: "Following a meeting with staff this morning, I can confirm the collective consultation has failed to identify a viable alternative that would allow the airport to remain open.

"Proposals put forward by staff were carefully considered by the management and owners but these proposals would still have required ongoing substantial losses be subsidised and therefore were not viable.

"In the absence of other options, the decision has been taken to close the airport on the May 15.

"Individual consultation will now take place with all staff members who will be supported through this process.

"This has been a very difficult time for everyone who works at the airport and we would like to thank all staff for their professionalism over the last few weeks."

The airport was bought for £1 by Stagecoach founder Ann Gloag in November, who launched a consultation on its closure in February.

It came amid estimates the airport had been losing up to £10,000 a day.

Today's announcement follows an offer from an American company to buy the airport, which was turned down over the weekend.

RiverOak Investment Corp LLC of Stamford, Connecticut, announced details of the bid today, saying it offered a long term plan to save the site, backed by $350m of assets.

However, the closure confirmation could be a blessing in disguise according to some campaigners.

Why Not Manston? chairman Nicholas Read said: "In some ways this is good news.

"It clears the deck for any possible new owner and makes it easier for them to start up again with fewer people and more certainty of covering their costs.

"Given the present owner doesn't intend to keep it open as an airport and is in talks to sell it, then to close it when it has been arranged for people to be made redundant makes it easier for a new owner to come in.

"With everyone pointing out the advantages of the site, potential new owners will realise there is a lot more going for it but it may have to be run slightly differently.

"That is what will probably emerge if a new owner can agree a price."

Individual discussions will now take place with 150 staff whose jobs are at risk.

Thanet District Council had been calling for the airport to be incorporated into the East Kent Enterprise Zone, a government designation that would have enable businesses to secure tax breaks.

Leader Clive Hart said: "It is not good news and not what any of us wanted to hear.

"You can only hope that the deadline might lead to pressure on other interested parties to come forward before May 15. Anything that we can do to improve the viability, we will."

In a joint statement, Thanet MPs Sir Roger Gale and Laura Sandys said their main concern now is for the workers at the site.

It said: "The statement released by the current owners of Manston Airport today is very saddening indeed.

"We know that there is ongoing and serious interest in the acquisition of Manston as a working airport and we hope that even at this late stage the current owners may be persuaded to reconsider and negotiate.

"Our first thought has always been for the employees of Manston, many of whom have families to support.

"We will absolutely not accept second best and will fight together in the coming weeks to make sure the interests of the people of Thanet are protected..." - Thanet MPs' statement

"Their wellbeing is of the upmost concern, and we will be making ourselves available for anyone who would like to meet us and discuss their concerns and options.

"Our second priority has been to establish the viability of Manston as an operating airport in the local and national interest. We are convinced that, given more time, real progress could have been made and it is thus hugely disappointing that the decision has been taken to close it.

"The both of us have always said that had we known about the owners’ intentions months ago, a plan could have been put in place well in advance and this continuing uncertainty could have been avoided.

"We wish to pay tribute to the local community who have been so vital in keeping the momentum around the airport going, and urge local people to keep faith that a positive solution for Manston will be found.

"We will absolutely not accept second best and will fight together in the coming weeks to make sure the interests of the people of Thanet are protected."

Kent County Council leader Paul Carter said: “This is clearly a difficult time for those who work at the airport and for those who depend on its aviation business.

"My concern throughout is to make sure that, whoever owns the airport, there is a viable plan for jobs and economic development in east Kent.

"The council is ready to offer any help it can to support future investment – and to back those who are committed to making a successful business in Thanet."