A fire investigation has been launched after a large blaze destroyed factory equipment worth about �1m on an industrial estate in Lenwade.

Firefighters from Reepham, Earlham, Carrow, Wroxham, Loddon and Dereham were called to One Way Circuits unit in Station Road, near Great Witchingham, at 6.22pm last night.

Phillip Leeder, watch manager of Reepham fire station, said: 'There was a large column of smoke coming from the building as we arrived. We were faced with a severe fire.

'We couldn't see flames initially but once the roof failed we saw the flames. It was quite dramatic. They were 20 feet above the building. Our main aim was to stop it spreading.'

No-one was in the two-storey building, which makes printer circuit boards, when the fire started and Mr Leeder did not think the blaze was suspicious.

He added that the flames did not spread to the other two parts of the business, which holds more equipment, or any other companies on the road.

The flames were put out within six hours of the initial call-out but crews were still on the scene this morning.

Throughout the incident, about 150 firefighters were called out and a water carrier from Hethersett and Fakenham, the environmental protection unit from Sprowston, an aerial ladder platform from Earlham and a control unit from Wymondham were in attendance.

Police were also called and a cordon was put in place as cylinders were thought to be involved. There was also the added risk of chemicals in the factory.

Richard Lyons, managing director of One Way Circuits, said he was uncertain about when the factory would re-open and everyone was worried.

The company was formed in 1987 and is the only one of its kind in Norfolk, supplying to different businesses across the country.

All of its 21 factory staff are full-time and do not know what is going to happen, according to Mr Lyons.

Mr Lyons was one of the final three people to leave the building and set the alarms at 5.55pm last night.

He said one of the company directors, Nigel Francis, was called at 6.15pm to be told the alarms had been triggered.

The managing director added that by the time he arrived at the business minutes later he saw firefighters smashing in the front doors.

'They were big flames. I drove past the Bernard Matthews site and saw the big black smoke and I thought it wouldn't be good. By the time I got here the flames were billowing out of the building.

'There seemed to be an awful lot of firefighters. I have never seen so many of them, but they prevented the flames from spreading,' Mr Lyons added.

There were between 40 and 50 machines in the area which was destroyed by the fire, ranging from one year old to 10 years old.

Mr Lyons said the business would try to get orders made by subcontractors but it could be months before its own factory would re-open.

Police officers helped the fire service with the closure of Station Road and urged residents to remain indoors and keep windows and doors closed last night.