CONTRACTORS were working to replace ageing gas mains in West Street before the explosion.

Homes in the street had been reconnected that morning.

Investigators have stressed it is too soon to say exactly what caused the blast on Monday, but there is speculation it was due to a fault in the main outside or in an appliance inside the house.

A company spokesman said: "We are co-operating fully with the fire service and Health & Safety Executive in investigating the cause of the explosion.

"Wales & West Utilities is undertaking gas mains replacement work in Malmesbury and part of this work has been renewing mains in Horsefair, but it is not possible to say if this incident is in any way related at the moment."

On Tuesday press spokesman Steve Kent said work would be suspended until the cause was discovered but reassured residents the area was safe.

North Wiltshire District Council building control manager Nigel Daniels said: "It is difficult to ascertain exactly what the cause of the explosion is."

Work on the gas mains in Malmesbury is part of a multi-million pound programme to replace crumbling pipes.

When they started the scheme last autumn Wales and West Utilities stated the work was essential to improve safety.

It involves replacing up to 180 metres of mains and installing durable plastic pipes within 30 metres of buildings.

The new pipes will have an 80-year-lifespan.

The firm joined forces with Scottish and Southern Electricity, which is replacing cables, and the project started with the closure of Oxford Street.