Plans to renovate hospitals in west Hertfordshire have been slammed as unfeasible by an expert in hospital construction.

Robert Scott was commissioned by the New Hospital Campaign (NHC), who are fighting for a new hospital central to St Albans, Watford and Dacorum, to study the NHS's proposals to renovate hospital services at Watford General, St Albans City and Hemel Hempstead.

Herts Valleys Clinical Commissioning Group (HVCCG) and West Herts Hospitals Trust (WHHT) face a funding limit of £350 million, and plan to use the bulk of the budget to renovate Watford General, with smaller renovations in Hemel and St Albans.

In a 35-page report for the NHC, Mr Scott said there is "no prospect of constructing a credible redevelopment or new build plan within that limit", and described the feasibility of the plans as "unproven and the subject of major doubt".

A statement from the NHC said: "[Mr Scott] states that the assumptions made about costs have many flaws, and concludes that the cost impact of the selected option is much greater than building a new hospital on a clear central site, so the latter option should now be reevaluated."

"A single site new build could be constructed for a broadly similar figure, but savings could be made to the cost which would not be possible via redevelopment."

The report argues that if the buildings were simply redeveloped it would not be possible to establish their 'hidden conditions', and also argues the redevelopment would take double the amount of time than the estimated three years.

Members of the campaign group recently launched legal action against HVCCG, calling for a judicial review which would scrutinise whether further public consultation is required.

A spokesperson for HVCCG confirmed that they are reviewing the claim with their legal advisors, and will soon lodge a response with the court. Previously the CCG and WHHT have completely ruled out the possibility of a new hospital, saying "in order to secure much-needed funding out submissions must be affordable and realistic".

NHC is trying to raise £20,000 to fund the legal action. To donate go to https://www.crowdfunder.co.uk/new-hospital-campaign