When it comes to anticrime measures, there is one thing that criminals in the UK dread most.No, it’s not dogs, security guards, high-tech alarm systems or even the long arm of Scotland Yard.They fear UV light and the specially coded water that it detects.A recent survey conducted by the University of Leicester found that the crime-fighting approach most likely to stop thieves in their tracks is an invisible liquid that is sprayed on a perpetrator and that then can be detected under ultraviolet light. The water is secured in canisters that are positioned at strategic points. When unsuspecting intruders trigger the system, the harmless liquid is released. Individual items also can be tagged with the watermark, allowing for easy identification if stolen.A survey found that criminals in the UK were deterred most by a security system that leaves an ultraviolet tag on their skin and clothing. Courtesy of SmartWater Technology.The liquid has a DNA-style code that can take months to wash off entirely and that directly links a criminal to a crime scene. The study of criminal behavior concluded that the system from SmartWater Technology Ltd. was a better method of preventing crime than all other techniques, even high-profile police patrols.More than 100 criminals were surveyed, and 74 per cent of them said that SmartWater was a strong deterrent and that they likely would avoid burglarizing premises where a poster or sign for the system was displayed. Police in South Yorkshire have used the watermark system to secure 24 criminal convictions. Approximately 15,000 homes in Dorchester, where the research was carried out, use the device.