The ambitious application submitted to Swindon Borough Council by a local property developer to restore one of central Swindon’s most important historic buildings shows the scale of work needed.

Anthony Dallimer, who runs William Arthur Property based in the town, has agreed to buy Apsley House from Swindon Borough Council.

But that sale is dependent on the property company getting approval for its plans to convert the Regency mansion house into shops, a restaurant and café and a space for remote workers.

The application was put in late last year. But a document recently added, a revised design and access statement, shows some of the state of the 1830s building after decades in use as the home for Swindon Museum and Art Gallery.

The new update shows pictures of what it calls “unsympathetic interventions” to the historic fabric of the Grade II-listed building, such as original window shutters cut short to allow for the installation of modern radiators and heating pipes and boxed electrical cables being very visible on walls, as well as evidence of damp and rot.

The application pulls few punches, and says: “Both proverbially but also physically, there is a lot of rot that need addressing in the refurbishment of Apsley House.

“Not only is the roof made of asbestos, but poor maintenance and recent roof leaks have caused damp, internal damage and fungi growth. The charity Save Britain’s Heritage has added the building to its ‘buildings at risk’ list.

“No intervention is without challenges and some change will be required to enable the successful re-use of the space that will incur the lowest impact in terms of change whilst providing for a vibrant and regenerative development."

It adds: “The challenge should not be underestimated. The viability of the project relies heavily on balancing the significant investment required to renovate Apsley House with the vision and the planning constraints.

"This includes: The substantial investment required to remove asbestos and unsympathetic services installed by the previous occupants and owners, Swindon Borough Council.

"Within Apsley House the surviving period features do succeed in lending the original house a charm that future tenants can recognise and appreciate.

"Intervention is therefore mostly confined to refurbishing key heritage fixtures and fixings and to remove the unsympathetic services and features added in later years.”

Because the proposal includes two shops on the ground floor of the main house, which need to stretch through two rooms, from the front to the back of the building, the company has told planners it will need to create a new door in the separating walls either side of the main central staircase.

As well as creating the retail units on the ground floor of the main building on the corner of Bath Road, the developer wants to make the first and much smaller second floors into a co-working space.

It will revamp the extension just around the corner in Victoria Road, cladding it in timber slats for a more contemporary look, and use the ground floor for four shop units accessed from Victoria Road, with the second storey used as a restaurant.

Drawings included in the plans show the plot of land at the corner of the roads will have a wall built and the outdoor space will be landscaped to create a seating area, with steps and a natural ramp leading from the front of Apsley House around the corner.

As part of the deal between the development company and the council, William Arthur property can withdraw from the sale agreement if planning consent is not given by November 2024.