Emergency services were called at 3.37am to the blaze at Rollalong Hire Limited, a portable accommodation company on Penshaw Way, in an industrial estate in Birtley, Chester-le-Street.

A spokesman for Northumbria Police said: "A number of gas cylinders were found at the scene and a 300 metre cordon put in place."

He said that the cordons were scaled down after 7am and some of the residents were allowed to return to their properties.

A number of roads in the area were closed and people working at the estate on Saturday were advised to contact police on 0345 6043043 for more information.