A FIRE which seriously damaged the Grade II-listed Alston Hall could have been started deliberately, police have said.
Officers have started a joint investigation with the fire service into how the blaze started.
A police spokesman said: “The investigation will include the possibility that the cause of the fire was suspicious.”
The blaze ripped through a 19th Century mansion near Longridge, which was under renovation and a large section of the Gothic-style building was destroyed.
Around 75 firefighters tackled the blaze after the alert was raised at 10.40pm on Wednesday.
A total of 10 fire engines were sent the scene as firefighters battled throughout the night to save as much of the structure as they could.
Water was collected from ponds and streams near the house to help fight the blaze.
There were no injuries reported as a result of the fire. Alston Hall, designed by architect Alfred Darbyshire, was built between 1874 and 1876 for colliery owner John Mercer.
It remained a family home until 1949 when the hall was sold to Preston Council for use as a Day Continuation College.
In 1974, the hall was bought by Lancashire County Council who converted it to a residential training centre. It was sold last year to a private buyer.
A police spokesman said: “We are currently working with fire investigators to establish how the fire started.”
The fire service spokesman, said: “At least 60 to 70 per cent of the roof has been destroyed and that’s obviously then affected the third and second floors of the building and some parts of the first floor. We have managed to save the chapel, which is attached to the building, and the fire hadn’t spread to that.”
A police spokesman renewed the force’s appeal for information about the fire.
He said: “If anyone was in the area before the fire began please contact police with any information on 101 quoting log 1637 of March 15.”
No arrests have been made by the police and nomore information as to why it could be suspicious have been released.