The cause of a blaze which destroyed a Telford factory remains a mystery, investigators said today. Firefighters are still unable to get into the shell of Mail Solutions, Halesfield 14.Fire ripped through the premises on Thursday, and investigations are continuing to discover how the fire, which is not being treated as suspicious, may have started.

Workers were forced to flee the building as flames reached the roof. Staff from nearby businesses were also evacuated amid fears it could spread.

Today Martin Timmis, Shropshire Fire and Rescue Service fire investigator, said: “We are still waiting to interview some of the key witnesses to the fire.

“Firefighters have not been inside the building as it is still deemed as unsafe. We are unlikely to need to go into the building in terms of the investigation, however, as due to the severity of the fire there would not be any evidence.

“We are not treating it as suspicious at this stage. We hope to conclude the investigation into what started the fire by the end of next week.”

Fifty firefighters from across the county were involved in the battle to control the blaze, which started shortly after 4pm.

Thick black smoke was sent billowing into the sky by the fire at the building, which contained bales of paper and envelopes, as firefighters on aerial ladders pumped gallons of water onto it. Parts of the brick building collapsed along with the roof.

The blaze forced police to close off Halesfield 14. Staff fled the burning building, leaving behind their personal possessions, including keys for their cars parked outside.

Nobody from the company was available to comment today.