EMERGENCY services were put on standby and staff at the town hall were ready for a mass evacuation in London Road, Chippenham, after a live electricity cable snapped in half.

And because the electric cable was on the pavement at least six people were trapped in their homes.

People living along the road saw flashes of blue lights and heard an explosion just after 10am on Monday.

Police received the first 999-telephone call at 10.15am from someone who had seen the cables swaying dangerously.

Seven minutes later a second caller rang the control room and said the live cables had come down.

As soon as police officers arrived at the scene they smelt gas and cordoned off the road.

Fire crews were drafted in and the road was closed between the petrol station and the roundabout at the Causeway/ London Road/ Avenue La Fleche.

Staff at the town hall started planning an evacuation.

Town clerk Laurie Brown was in the thick of the evacuation of hundreds of people in 1998 when an unexploded bomb was found on the site where Abbeyfields School now stands.

He said: "At that time we had hundreds of people in both the town hall and the Neeld Hall. On Monday we took a call and were asked if we could make somewhere available if it was needed."

But it proved not to be the case.

Police Inspector Ray Josey said it had been safer to keep people away from the live wire.

We had to keep people in their homes because the electric cable was across the pavement," he said.

"The smell of gas was purely coincidental. Transco came out to the site and said people could smell gas because there had been an earlier leak in Calne.

Builders were working at the old gas yard site when a cap was knocked off a gas pipe and the smell carried to Chippenham

Margaret Andrews and her husband Roy saw the cables sway and then arc loose and fall on the pavement.

"We were told to keep away from the front of the house because they could smell gas and didn't know at that time where it was coming from," said Mrs Andrews.

Bob Swaffield feared his computer would never recover from the power surge. He was at his desk working when the computer suddenly shut down.

"Everything else was working. I thought something had overloaded the computer. There was smoke coming out of it," he said.

London Road resident Christine Doman said a fire fighter knocked at her door and told her family to stay inside and near the back of the house.

An ambulance was on standby and a policeman stayed with elderly neighbour Ethel Few until the crisis was over. She suffers from severe asthma and her nebulizer relies on the electricity supply.

At least 150 customers were affected for at least four hours and 25 households were still in the dark at 5.30pm. The last person had their electricity switched back on a t 7.15pm on Monday night.

About 150 metres of cable was replaced. Denis Kerby, spokesman for S+S, formerly Southern Electric, said the combination of the freezing temperatures and the location of the cables near trees had possibly caused them to snap.

"They have been replaced with new design cables which enclose the four wires in a protective covering," he said.