The fire service has revealed the cause of a huge blaze in Bitterne that shut a main road for almost 12 hours.

Plumes of smoke filled the Southampton skyline on Sunday, July 14, as around 80 firefighters tackled the inferno at an industrial unit on Bitterne Road West.

After weeks of investigation, Hampshire Fire and Rescue Service has now given an update on the official cause of the fire.

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More than 80 firefighters tackled the blazeMore than 80 firefighters tackled the blaze (Image: Submitted)

A spokesperson said: “Our Fire Investigation Officers have concluded that the Bitterne Road West garage fire in July was accidental, believed to have started within a vehicle.”

The fire in the yard outside the Ravenscroft Motor Company was quickly reported to the fire service by an employee.

As flames spread to houses marquee lining manufacturer Customer Covers nearby, police shut the busy Northam Bridge and directed residents away from the area of the fire.

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The fire could be seen from across Southampton The fire could be seen from across Southampton (Image: Submitted)

Robert Saunders, CEO of Customer Covers, spoke to the Echo about the fire in the wake of the incident.

He said: “On the morning of July 14, Custom Covers Ltd of Quayside Road in Southampton had a major fire which destroyed its raw material stores and linings hire departments.

"The fire was reported by an employee of the Ravenscroft Motor Co Ltd, on Bitterne Road West in Southampton, who saw one of the cars in its yard going up in flames.

“The fire spread to the neighbouring property owned by Custom Covers Ltd.

“Custom Covers praised the Fire Brigade who were on site very quickly and got the fire contained. No one was hurt in the incident.”

Drone footage taken on the day shows a massive plume of smoke rising over the site, while other video taken by residents shows the flames rising above hedges as firefighters fought to bring the fire under control.