Herts Fire and Rescue Service has confirmed why smoke was seen rising above Costco Watford.

Two fire engines were sent to the membership warehouse, in Hartspring Lane near the A41, at around 12.52pm today (September 7) following reports of smoke having been seen by members of the public nearby.

Firefighters have confirmed that a small fire on the roof had been caused by ongoing works at the site, but the flames were already out by the time the fire service arrived.

Staff at the store said that there was "nothing to report" and any disruption appears to have been minimal.

A motorist passing by said: "I was driving towards Costco down Aldenham Road, away from the Bushey Sports Club.

"Thick black smoke was high in the sky over Costco."

Hartspring Lane is not only home to a supermarket but acts as Costco’s UK headquarters as well. The site also contains a popular petrol station.