Epsom and St Helier trust has said none of its buildings are fit for purpose and it is to start to looking at options for the future of its sites.

It believes it would require £500m worth of investment for Epsom, St Helier and the land it owns on the old Sutton Hospital site to be turned into hospitals fit for the 21st century.

The trust board agreed at a meeting on Friday that an "estates review" being conducted by the trust and Surrey Downs and Sutton Clinical Commissioning Groups, could start identifying options for where services should be provided from in 2020 and beyond.

It said the work "feeds into" a strategy being developed for hospitals across south west London led by another body, South West London Collaborative Commissioning (SWLCC).

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The estates review has so far involved the trust considering how adequate its buildings are and how much money is needed to improve them.

The board agreed to allow a second phase to now begin, allowing the trust to identify options for the sites and consult with the public.

The trust said it aims to "come back in the autumn with some options for the future".

In a document setting out the review, the trust said it is "committed to retaining both Epsom and St Helier hospitals for at least the next five years".

But, in the longer-term, it added: "Achieving high-quality buildings is not possible without major transformation.

"Achieving our aim for our buildings, we will need to do more than refurbish.

"The trust therefore needs to look at options for redeveloping and rebuilding its estates."

At the meeting, the board heard how none of the trust’s buildings are fit for purpose.

Dr Claire Fuller, clinical chair of Surrey Downs CCG, said she had seen patients being wheeled between buildings at Epsom being protected by umbrellas.

The trust said more than 90 per cent of St Helier was built before the NHS was founded and more than two-thirds of Epsom is 30 years old.

Daniel Elkeles, trust chief executive, said: "We remain absolutely committed to no change for the next five years, as we have always said.

"But we simply have to put longer term plans in place, from 2020 onwards, if we are to continue delivering the high quality care local people deserve."

The board said the recent offer of help for Epsom Hospital from successful businessman Sir Adrian White - as revealed exclusively by this newspaper - was very welcome, but it needed to be considered alongside a range of other options.

It said it wanted to organise visits to the hospital sites so people can see for themselves the problems.

Laurence Newman, board chairman, said after the meeting: "We need to plan for the long-term with the full involvement of our local population, our local health partners, and the wider NHS and play a full part in any wider reviews of services going on across south west London.

"Now we have completed the first stage of this process looking at our estate and assessing where it falls short, we will be able to explore in more detail how to improve it, including a properly informed, properly engaging conversation with our patients, our partners and the public about what they want from local hospitals and what criteria we should use to evaluate future options."

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Announcing the SWLCC issues paper, Dr Chris Elliott, Sutton GP and senior responsible officer for SWLCC, said: "The challenges set out in the issues paper are matters we have been raising for several years.

"The case for change is much the same as that outlined in the past but the problems it causes are getting worse.

"The financial case for change is also broadly the same - without changing how the money is spent, in five years’ time we will not have enough money to pay even for the services we deliver today."

He added: "There is a broad consensus within the local NHS that things need to change - and we know that we cannot go on as we are.

"This is not a public consultation - there are currently no plans to make the kind of major changes that require public consultation.

"If we do develop such proposals, we would certainly consult on them."