A former chemical factory on a Bristol site used to produce mustard gas in World War I was reduced to a pile of metal today.

At noon the Rhodia Chemical Factory, in Kings Weston Lane, stood on a derelict site but seconds later it was nothing more than a heap of mangled steel.

Specialists in explosions and the removal of hazardous materials Lee Demolition Group, used 25 kilos of nitroglycerin, or dynamite, to demolish the 100ft factory building.

Managing director David Lee, 37, pressed the button on his first demolition when he was just four.

He said: "It's taken about four days to prepare the site. It's involved some pre-cutting within the building. This demolition is quite difficult as the structure is heavy duty.

"It also can be quite hazardous because of chemicals so we've had to do all the environmental checks beforehand. We added a charge to 18 of the legs the factory stands on and added the nitroglycerin. Once the button is pressed it sets off the charge."

A siren sounded as a warning before the sand-packed legs were blasted into oblivion. Within seconds a wave of dust filled the air as the building came crashing down.