The reason behind a major fire in Swindon which caused multiple fire services to attend the blaze for four hours has been revealed.

The fire broke out at the Swindon Powertrain workshop in Crampton Square just before 4pm yesterday (Friday, December 8).

The workshop was "badly damaged" by the fire with one vehicle inside the building being completely destroyed by the flames.

Dorset and Wiltshire Fire Service said crews from multiple fire stations were called to attend from Stratton, Westlea, Swindon, Marlborough, Royal Wootton Bassett, Chippenham, Fairford, Cirencester and Faringdon.

Also on scene were the aerial ladder platform from Swindon and an incident command vehicle from Devizes.

Swindon Powertrain is a manufacturing company which makes engines for the British Touring Car Championship and provide “complete electric vehicle solutions and internal combustion engines”.

Crews battled the fire at Swindon Powertrain's workshop for almost four hours as local residents were warned to stay inside their homes and keep all windows and doors closed due to smoke.

At its height, the blaze at Compton Square could be seen from Greenbridge Retail Park and locals were urged to avoid the area.

Explaining the cause of the fire, a spokesperson for Dorset and Wiltshire Fire Service said this morning: “The fire started accidentally with an electrical fault in one of the vehicles. We had left the scene by 8pm.

“One vehicle within the building was destroyed, four more damaged and the workshop has also been badly damaged.

“12 breathing apparatus wearers had used three main jets and two hose reel jets to extinguish the fire.”

A full investigation will be carried out now that the fire has been extinguished, and Swindon Powertrain has been approached for comment.

Many onlookers were left standing in the cold with young children near the police cordon as they were told they were unable to retrieve their cars parked near the fire.

"I work down there and my car's parked down there but I've just been told I can't get it back until tomorrow," one father told our reporter.

Although no occupants were in the building when the fire took hold, Dorset and Wiltshire Fire Service has now confirmed that the workshop has been “badly damaged” and one vehicle has been destroyed with four more left in a bad state.

Swindon Advertiser: The workshop has been left 'badly damaged'.The workshop has been left 'badly damaged'. (Image: Dave Cox)

An AA statement on Friday issued at around 5pm said traffic was "coping well" in the area despite the road closure.