The social club at Penninghame House near Newton Stewart was gutted by a raging fire which took six hours to get under control.
Five fire crews spent most of Wednesday afternoon and evening tackling the flames in the club of the former open prison, which were first reported at around 12.30pm.
Part of the club, some 400 yards from the main house, collapsed and the structure is now way beyond repair.
Five fire appliances from Newton Stewart, Gatehouse, New Galloway and Stranraer rushed to the scene on the estate off the A714 ‘Girvan road’.
Lynn Taylor from the Penninghame House Foundation said it’s too early to tell if the building will be replaced.
She said: “The owners are in Sweden at the minute so without having spoken to them, it’s really too soon to say what will become of the building.
“But it’s completely gutted, there’s nothing left of it. It’s a self-contained building some distance from the house so at no time was the main house threatened, but there were some fears over the trees at the back catching fire.”
The fire crews also worked furiously to cool down two propane gas cylinders inside.
Penninghame House and its outbuildings are currently used for cooking and residential wellbeing courses after being bought by the Butler family in 2000.
The social club was used by prison staff and locals as a pub and venue for parties and gatherings throughout the lifetime of the prison.
The cause of the fire is under investigation but is not thought to be suspicious.
On the same day, grass burning on the banks of the River Cree in Minnigaff temporarily flared out of control and filled the area with smoke.