A blaze broke out in a demolished chicken shed at a Burnley village farm.
The fire swept through a huge pile of shed timber and waste on land off Heckenhurst Avenue in Worsthorne on Sunday evening.
Firefighters were called to tackle the “suspicious” blaze at 5-15pm after a plume of thick black smoke was seen rising above the Burnley skyline.
Watch manager Neil Ashworth, of Burnley Fire Station, said the fire was difficult to deal with and was left to burn under control.
He said: “The fire was very deep-seated. There was not much we could do. We will keep a presence up there. It will keep burning until we are able to dig it out.”
The fire is believed to have been started deliberately as the farmer spotted youths playing in the area.
A digger was being drafted in to help dig out the fire.