Bedfordshire fire fighters tackled a blaze at a large disused house in Clifton near Shefford during the night.
The first and second floors and the roof of Clifton House in Church Street were all well alight.
Local residents say the unoccupied listed building, which was built in the late 18th and early 19th century, has been the subject of planning application to convert it into flats.
Last year there were reports of vandalism carried out by youths who tried to start a fire.
