Futuristic plans to turn crumbling Putney Hospital into a multi-million pound medical centre have been undermined by soaring costs.

At £4million, the subterranean car park became the main stumbling block, judged too costly because of its two storeys and the annual waterlogging of the site in winter.

But overground parking will mean delays as the need for a redesign has sent the project back to the drawing board.

Bosses at Wandsworth Primary Care Trust (PCT) have also decided to review the quantity and the style of housing that was planned for the new primary care centre.

John Horrocks, of the Putney Society, said a PCT representative told a meeting of the patients' forum in October that quantity surveyors' cost estimates were running at £10million more than anyone had predicted, leading to the radical rethink.

Mr Horrocks questioned whether Putney Hospital was the best site for the centre, saying: "It's perfectly understandable that if it's wildly expensive then you've got to think again.

"But there is a question over whether the site is big enough for all they want to do. Is this the right site for a development as big as they want to make it?

"There is some way to go before they can show it all works."

A PCT spokesman said it was still committed to using the derelict hospital site for the project, which would amalgamate three GP surgeries, include pharmacy, dentistry and chiropody, and have 80 to 100 car parking spaces.

He added: "There is plenty of space for the primary care centre, which is the focus of the development.

"The PCT undertook a search for other sites in Putney only a few months ago, which showed that there were no other sites that are both affordable and available in the time frame required."

He said the project's steering committee would receive a progress report this month, and if it contained an affordable, well-balanced option, the PCT could make its business case and have a better idea of the delays that occurred.

He said this was normal procedure for an NHS development, and was designed to ensure best value was achieved on the site.

He added cash saved from the underground car park would be put into providing "first-class primary care" for Putney.