THE cause of a £3million factory blaze will not be known until at least the middle of next week.

Fire investigation experts are continuing to interview personnel at Pine Direct, Burnley, which was gutted in a devastating fire.

One of the possibilities under investigation is that a heater was too close to combustible material.

Fire and Rescue Service Divisional Officer Stuart Tracey said: "We are still looking into the cause.

"Our inquiries have not been finalised, that could take until the middle of next week.

"We don't rule anything in or out but initial inquiries lead us to think it was not suspicious."

Fire crews are still at the scene to dampen down the smouldering remains.

They are now waiting for demolition workers to clear the twisted debris so that they can get to the seat of the fire.

Flames swept through the 250-yard long building after the fire broke out shortly after noon on Thursday. The 100 workers all escaped unhurt.

Employees who tried to put the fire out were beaten back by the flames.

More than 120 firefighters from all over the county tackled the blaze for two hours as a column of black smoke rose hundreds of feet into the air above the site off Accrington Road.

Company bosses have pledged that jobs are safe. Marketing manager Paul Hibbs said they were urgently seeking temporary accommodation until they could redevelop the site.