A fire at a £4m supermarket in the fens was caused by an electrical fault, it was revealed last night. The fire was on Thursday at the Rainbow Superstore at Elm on the Norfolk and Cambridgeshire border.

A fire at a £4m supermarket in the fens was caused by an electrical fault, it was revealed last night.

The fire was on Thursday at the Rainbow Superstore at Elm on the Norfolk and Cambridgeshire border.

Fire crews from across west Norfolk and the fens took more than four hours to bring the blaze under control.

A spokeswoman for the Anglia Regional Co-op, said the company was awaiting the results of a structural engineering report, and any timescale on re-opening would depend on what the report said.

Speaking last week, Neil Double, chief executive of the Anglia Regional Co-op, said the store's staff would be redeployed to other stores within the group until the Elm store was ready to reopen.

Fire investigators have examined the debris and discovered the seat of the fire was believed to have been electrical.

A spokesman for the Norfolk Fire Service said: "The firefighters did a good job stopping the fire and the crews deserve commending for the fine job they did on the day.

"The fire investigation has now concluded."

Cleaners raised the alarm just before 7am and within an hour crews from King's Lynn, Wisbech, Downham Market, Terrington, Outwell and South Lincolnshire were at the scene, off Elm High Road.

A plume of smoke could be seen for miles at the height of the drama, as 14 appliances, including a turntable ladder, attacked the flames.