FIREFIGHTERS had to evacuate a burning factory unit after the roof began to collapse.

Flames then rose out of the top of the empty unit, at the Imperial Mill Industrial Estate in Liverpool Road, Burnley, last night.

Fire crews used an aerial ladder to tackle the blaze, which is suspected to have been started by arsonists at about 6pm.

The industrial estate is empty and awaiting demolition by a property developer.

But the unit - formerly used by Woodfield Printers - contained combustible materials, causing a major fire, said Andy Barnes, station manager at Burnley fire station.

He said the intruders knocked down a breeze block wall to gain access to the two-storey unit and the fire could potentially have engulfed the whole site.

Station manager Barnes said: "Our initial findings are that it has been caused deliberately. Speaking to the occupants of the adjoining unit the place does have a history of vandalism and unauthorised access.

"What was left inside of the building was things like palates and other combustible materials like piles of timber and plastic."

"It could quite easily have spread throughout the site."

A total of 25 fire brigade personnel attended the fire with fire engines from Burnley and PadIham. Burnley's environmental protection unit and the incident support unit from Accrington also attended.

Security had been placed around the unit last night.

The site has been bought by Nelson firm Barnfield Construction and a meeting scheduled for today over when to begin demolition of the site will go ahead as planned.