The estimated cost of urgent work to restore a dilapidated park and its endangered historic buildings has leapt by £3.6 million, according to a new report.

Gunnersbury Park, on the borders of Brentford and Acton, is in urgent need of attention, with several buildings on English Heritage's 'at-risk' register.

Ealing and Hounslow councils, which jointly manage the 75 hectare park, are working on plans to refurbish it in time for its centenary in 2026.

They had estimated the first phase of regeneration alone, including restoring the museum in the park's large mansion and several other grade II-listed buildings, would cost £17.3 million.

However, surveys have indicated the park is in a worse condition than first feared, pushing the anticipated bill for the initial round of work to £20.9m.

The two councils are expected to put £8.2m of capital funding between them towards the cost and are due to bid shortly for £7.7 million from the Heritage Lottery Fund (HLF).

They now plan to apply for an extra £1.1m 'uplift' funding from the HLF, with the rest of the shortfall to be met by a mixture of additional grants, savings and more funding from the councils themselves.

Details of the increased costs emerged in a report by Councillor Ajmer Grewal, Hounslow Council's cabinet member for leisure, published on Monday (February 4).

In it she writes: "A significant increase in costs is expected following detailed surveys of the fabric of the large mansion and other buildings.

"The condition of both the internal and external fabric of the large mansion is worse than anticipated at round one (the initial planning stage of phase one)."

Her report does not state whether the overall cost of the regeneration project, due to be completed in three phases, has risen from the original estimate of £48m.

* A meeting to update people on the latest plans for the park and the results of public consultation on the phase one proposals is due to take place next Tuesday, February 11, at Gunnersbury Park Museum, in Popes Lane, Acton, from 6pm to 8pm. To book a place, email gunnersbury@ealing.gov.uk.