Five fire crews were called to an arson attack at a large warehouse in a residential area of Preston.
Firefighters were called to the former Bookers cash and carry building in Holme Slack Lane, Deepdale, Preston, at around 4.15pm on Saturday.
Old stock inside the 30m x 80m single storey warehouse, which is close to the Aldi store at Deepdale Retail Park, was set ablaze and crews were at the scene for several hours tackling the flames with jets and hose reels.
Lancashire Fire and Rescue Service said four fire engines and an aerial ladder platform were at the incident as of 6pm.
Acting watch manager Patrick Barlow said he believed the fire had been started deliberately.
He said: “There have been far too many previous fires in this building.
“It was difficult because the electricity was still alive and we couldn’t put water on it and had to wait for a while until the electricity was isolated.
“There was damage to residual stock still in the building. It is just a maze of supporting timber walls.”
He said the blaze was out by 7.30pm.
* Do you have pictures of the fire? Email email@example.com