Police are investigating the cause of a “large” van fire which broke out twice last night.

Witnesses called Herts Fire and Rescue with reports of the vehicle ablaze in Berry Avenue, Watford, at 8.54pm yesterday (April 4).

A Garston Fire Station crew arrived and found the vehicle “well alight” before putting it out and leaving by 9.40pm.

Watford Observer: The fire (the second time it broke out) in Berry Avenue, Watford.The fire (the second time it broke out) in Berry Avenue, Watford. (Image: Contribution)

But then just after 10pm the service was called again with reports that it had reignited, following which firefighters returned to the scene.

“Firefighters extinguished the fire and thoroughly damped down the scene, before handing the incident over to the police,” a spokesperson said.

Watford Observer: The fire (the second time it broke out) in Berry Avenue, Watford.The fire (the second time it broke out) in Berry Avenue, Watford. (Image: Contribution)

“An investigation into the cause of the fire is taking place this morning.”

An eyewitness told the Watford Observer that they did not see the initial "large" blaze start but by the time they noticed it the van was “covered in fire”.

After fire service left, they spotted the bottom of the van had started “sparking” before the fire began “growing and growing” until it engulfed the vehicle again.

Watford Observer: The fire (the second time it broke out) in Berry Avenue, Watford.The fire (the second time it broke out) in Berry Avenue, Watford. (Image: Contribution)

This morning, a Herts Police spokesperson confirmed: “It is the believed the fire was started deliberately and enquiries are continuing.

“Anyone with information is asked to please contact police, quoting crime reference 41/27114/24.”