Craig Baker/Dorset and Wiltshire Fire Service
The fire at Parnham House has badly damaged the 16th century home
The blaze, at the 16th century Parnham House in Beaminster, Dorset, broke out in the early hours of Saturday morning.
Firefighters were called just after 4am and found the property well alight.
Photos taken by Dorset and Wiltshire Fire Service show huge flames ripping through the home.
A fire service spokeswoman described the fire as "extensive" and added: "It is not believed anyone was inside the property and there are no reports of any injuries.
"At this stage the cause of the fire is unknown; however, police are treating it as suspicious and an investigation is under way."
Craig Baker, area manager for Dorset and Wiltshire Fire Service, tweeted that there were 20 pumps at the scene, as well as an aerial ladder platform and water carrier.
He added: "A devastating fire, crews have worked tirelessly. Remains a big firefighting operation!"
Photos taken after the blaze was brought under control show at least part of the roof has been destroyed.
Parnham House is described as an "exceptionally important mid-C16 house" by Historic England.
The fire is being treated as suspicious
It was built for Robert Strode and Elizabeth Hody in 1522, and was renovated in the early 1800s.
Furniture designer John Makepeace bought the property in 1976 and ran his School for Craftsmen in Wood in the house.
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It was then bought by Michael and Emma Treichl in 2001, who carried out extensive renovation.
The home has been badly damaged by fire
Parnham House has been described as "exceptionally important"
As pointed out by @LostHeritage, Parnham House is the fifth historic stately home to fall victim to fire in a little over six months.
The fire follows devestating blazes at Cosgrove Hall in Northamptonshire, Kelsale Hall in Suffolk, Alton Hall near Preston and New House Hall in West Yorkshire two days ago.
Only Parnham Hall is being treated as suspicious.
Anyone with information is asked to contact Dorset Police online, via 101 or call Crimestoppers anonymously on 0800 555 111.