Police are hunting arsonists who struck at a late 19th-century mill in Silsden.

Huge plumes of smoke enveloped the town last Thursday as flames ripped through the roof of Becks Mill, off Keighley Road, just after 5pm. A nearby petrol station had to be closed for customers’ own safety while firefighters from across the district fought to quell the blaze throughout the night.

Bradford councillor for the Craven ward Andrew Mallinson said he could see the inferno from his Steeton home.

He said: “It was huge — the flames were visible from my house, which overlooks the town, and they must have then taken hold of the building because smoke was billowing out.”

Crew manager for Keighley fire service Joe O’Keeffe confirmed that the 1885 mill’s roof had been extensively damaged and he said private security guards were now on site to ensure nobody entered the building.

The mill was the former home of Riverdale Publishing and had not been used since the company went into administration 16 months ago.

Surveyor Brackenridge Hanson Tate has been trying to lease the building on behalf of a “significant property landlord investor” for some time.

Partner in the firm Mike Atkinson said: “There have been several break-ins there since it has been vacated. Obviously there will be significant damage to the building, which we are assessing this week, and a decision will be made in the near future as to whether it will be repaired or demolished.”

A spokesman for Airedale and North Bradford police said: “On further investigation the incident is now being treated as arson. Inquiries are ongoing and anyone who saw what happened or has information should contact PC 6332 Adam Taylor, at Airedale and North Bradford police, on 0845 60 60 606.”