AROUND 40 firefighters tackled a blaze overnight in a derelict mill which had 5,000 gallons fuel stored inside.

The crews from Barnoldswick and Earby led the operation from around 9.50pm, with the damping down processes continuing into the early hours.

Firefighters quickly dealt with the fire in Fernbank Mill, Fernbank Avenue, Barnoldswick, to ensure that the heater oil on site did not ignite.

It is unclear at this stage whether the fire was accidental or deliberate.

But the fire was caused when oil from the tank in the 150,000 square foot mill’s boiler room began leaking and ignited.

Eyewitness Ralph Thurogood, 80, of Fernbank Avenue, Barnoldswick, said: “The flames were a third of the way up the chimney and I saw one fire engine after another and eight police cars at the scene.

“People were coming around from the area to have a look at it.”

John Taylor, from Lancashire Fire and Rescue Service, said: “There were a number of small oil fires in the vicinity which had leaked and ignited from the tank. But the tank itself did not catch fire.

“The heating oil is not as volatile as petrol or spirits.

“But firefighters did use water to cool the tank.

“An oil tanker has been to the site to decant and remove the oil from the premises.”

John Clarke, from Fernbank Shed Co which owns of Fernbank Mill, said a large part of the mill had been demolished and the fire caused very little damage.

Mr Clarke said: “The mill was well into the demolition and has nearly all been pulled down.

"The oil had been left on the site and hasn’t been used since last Christmas.”