The crumbling Lambton Estate could be saved and opened to the public as part of a £28.5m scheme.

Durham County Council looks set to give the green light to plans to build 400 houses and create 525 new jobs in offices on the estate between Chester-le-Street and Washington.

The plot is one of County Durham’s ‘hidden gems’ according to reports sent to planners, but has fallen into decline and is now at a critical point.

Money raised from building 400 homes would go towards conserving the 24 grade-I or grade-II listed buildings within Lambton Park.

If restored, Lambton Castle, which played a starring role in TV period drama The Paradise in 2013, could become a wedding venue or boutique hotel raking in £1.3m a year, land owners have said.

The park’s owners say it is an untapped attraction which could pull in 75,000 visitors per year.

Proposals include 9.3 miles of public footpaths on the estate which applicants, The Trustees of Lord Durham’s 1989 Voluntary Settlement, say will “deliver significant and unprecedented public access to the estate which would otherwise remain private”.

However, Durham County Council’s Right of Way Officer has called for more access to the 600-acre site.

He said: “Provision for enhanced public access to the Lambton Estate is extremely disappointing given both the size of the land area and the scale of the proposed development.”

The vast majority of the 400 homes proposed will be for the “upper end of the market”, which applicants claim is underrepresented locally.

Just 15% of the homes will be ‘affordable’ with 45 rented and 15 sold at discounted market rates.

The plans have the support of North Durham MP Kevan Jones, the North East Chamber of Commerce, Business Durham and Visit County Durham, though neighbouring Sunderland City Council has raised concerns over the impact on school places and the road changes proposed.

Councillors will discuss the plans on January 8.

The Lambton Estate has had a colourful history; in the 1970s the park was home to wild animals as Lambton Lion Park which was open from 1972 to 1980 when it closed due to alack of funds and problems with animals escaping.

In the 1960s large swathes of the former estate were sold off to developers to create Washington New Town following compulsory purchase orders.

The Lambton Estate, including Biddick Hall and Lambton Castle, has been owned by the aristocratic Lambton family and currently belongs to Edward ‘Ned’ Lambton the 7th Earl of Durham.

Last year, he settled out-of-court an almost decade long inheritance row with three of his sisters after he was initially left the entirety of his father Anthony Lambton’s multi-million pound estate.

Anthony, the former Conservative MP for Berwick, was forced to resign from Government after allegedly being photographed in bed with prostitutes and caught using cannabis in 1973.

Ned had said that his fathers wealth had been tied up in property and the family’s former Northumberland home, Fenton, is on the market for £10m.