A couple of workers at a store in St Albans could have been red-faced, but it was difficult to see their visages through a thick security fog screen that was accidentally triggered upon their arrival this morning (Tuesday).

Herts Advertiser: Security fog screen in action at the CeX store in Market Place, St AlbansSecurity fog screen in action at the CeX store in Market Place, St Albans (Image: Debbie White/Archant)

Historic Market Place, near the Clock Tower, quickly became filled with an artificial ‘security fog’ which erupted from the CeX store just after 8am.

Upon seeing the thick fog - which has no odour but looks like smoke - suddenly wafting down the narrow lane, the Herts Advertiser, which is located near the store, asked if the fire service had been called.

But two men at the entrance of the shop explained that it was not smoke, but “Fog Bandit” in action – a high density security fog system which helps deter intruders. It is harmless, but reduces visibility to less than 30cm.

CeX buys, sells and exchanges a range of technology and entertainment products including mobile phones, DVDs and computers.

Herts Advertiser: Security fog screen in action at the CeX store in Market Place, St AlbansSecurity fog screen in action at the CeX store in Market Place, St Albans (Image: Debbie White/Archant)