EMERGENCY crews have closed the A420 at the White Hart roundabout due to a major gas leak.

The busy A road is closed from the roundabout, past Gablecross Police Station and up to Watchfield.

A detour is in operation and drivers are advised to avoid the area.

The road closure is expected to be in place for the next couple of hours.

Police superintendent Phil Staynings said: “We received a number of calls relating to this gas leak this morning and we are on scene, along with representatives from the gas company and colleagues from the fire service.

"Specialist engineers are hoping to make the scene safe as soon as possible.

“We appreciate this is a major road and as a result there are likely to be long delays in the area so we would urge drivers to seek an alternative route where possible.

“Business is continuing as normal for officers based at Gablecross and we are responding to emergency calls as we normally would.” 

Vehicles over 14ft 6in have been diverted off the A420 at Watchfield. All smaller vehicles are being diverted through South Marston. 

The Swindon-Oxford Stagecoach 66 bus is also affected.

The gas leak was first reported shortly after 6am.

One woman claimed to have been shopping in Toys R Us at the time said the smell off gas was “awful”.

Trevor Clark, Wales and West Utilities Gas Emergency Service Manager for Swindon, said that third-party contractors working in the area had "seriously damaged" a gas pipe running beneath Shrivenham Road, causing it to leak.

He said: "Due to the scale of the damage that has been caused to the gas pipe, this is a complex job, and we are unable to say how long our work will take.

"Our engineers are working as safely and as quickly as they can to make a full repair and reopen the road, and we will keep the local community and road users updated.

“We appreciate that working on roads such as these is not ideal, but it is important that we fix this leak now, so we can keep the gas flowing to heat homes and power businesses in the area.”

Thara Raj, consultant in health protection for Public Health England, said: "The highest risk of natural gas exposure is suffocation in confined environments, and because the leak is outdoors this is not a risk.

"Repairs are being made to the affected pipe to minimise risk of explosion and risks to public health are low.

"In the unlikely occurrence that individuals develop symptoms, we would advise that they contact NHS 111 for medical advice.”

John Wilkes, 65, of Covingham, said he was asked to leave the Sainsbury's store: "They told me there was a massive gas leak. I just carried on shopping until they told me they were shutting."

Sainsbury's is understood to be open, although the road remains closed.