In a bid to cut forecourt theft, petrol stations are installing a DNA-based spray unit which coats robbers in an unwashable red dye.

The RedWeb device has been installed at Texaco petrol stations in Hertfordshire, Essex and London.

RedWeb Sentry sprays and marks offenders with a bright red staining dye that contains a non-washable unique DNA code. This code gives police irrefutable evidence that visibly marks the criminal and proves his presence at the scene of crime.

To date the system has been supplied for police operations but now it is being launched into the commercial market.

The forecourt industry is facing losses of £26m with a noticeable rise in gun related incidents.

The systems are being installed by Safe Homes (UK) of Tamworth, Warwickshire.

The installers are police trained forensic engineers equipped to respond to activations in the event of an attack and to assist the police in their enquiries and gathering of supporting evidence.

The highly visible forensic dye contains a unique biosynthetic DNA tag which links the criminal to the crime scene.

The fine mist will, in most cases, go unnoticed by the target and the company offers panic alarm training, subject to local police approval. Criminals will not know anything has happened until they leave the premises.

RedWeb (www.redwebsecurity.com) is about to launch an initiative with the National Federation of Retail Newsagents to make the system available to local "corner shop" businesses.