Nipping burglary in the bud: On your mark CRIMINOLOGISTS love to argue about whether acquisitive crime inexorably rises in hard times. Statistics helpfully provide evidence both ways. According to the British Crime Survey, domestic burglary in England and Wales grew by 10% in the 12 months to June 2011. According to police records, it fell 3% (though other sorts of theft did rise). What all can agree on is that burglary's long, strong decline over the past decade and a half has at least slowed. So attention is turning to various ways of deterring burglars, including ever-fancier alarms and a new interest in fierce-sounding hounds. But alarms are only as good as the police who respond to them quickly, and a 20% cut in force budgets is likely to thin their ranks. Dogs have an embarrassing habit of fawning on intruders. Against this background "forensic marking" with chemical lacquers and gels and greases containing unique codes is coming into its own. Some kinds can be painted on jewellery or iPods to identify their owner; others can be sprayed on the crooks who try to steal them. Among the firms selling these products, rivalry is fiercest between Selectamark Security Systems, many of whose formulae include DNA, and SmartWater Technology, which uses metal-oxide combinations that are invisible to the naked eye but glow yellow under ultraviolet light. Both firms say business is booming. Selectamark's sales (including those abroad) have increased by 40% in two years, according to Andrew Knights, its managing director. SmartWater's Phil Cleary says turnover has doubled in the same spell. Both claim their methods work. SmartWater trumpets a 100% success rate in obtaining 1,000 convictions over its 16-year existence, whereas Selectamark prefers to dwell on crimes prevented. Alan Given, a policeman who headed the Nottingham Crime and Drugs Partnership until 2010, says that domestic burglaries fell dramatically after the city deployed SmartWater in a big way. Other cities have similar tales. But chemicals are only part of the strategy; publicising their use to frighten burglars off is crucial. Buildings are covered with warning posters. Secondhand stores and scrapyards are handed gear to look for signs of theft. Police scan unsuspecting offenders of all stripes for the telltale yellow. A barrage of ads and YouTube clips ram home the message, true or not, that crooks cannot hope to escape the long arm of forensic marking. Word gets around. Over 1m households use SmartWater's services. Now other customers are looming larger, among them charities. Paul Ozanne, the national recycling co-ordinator for the Salvation Army, says thefts of clothes from bins have soared. He reckons his outfit loses 2,000 tonnes a year, mainly to gangs reselling the stuff in eastern Europe. With SmartWater's help, his charity has resisted the rising national trend and secured convictions. Where forensic marking is really winning converts these days is in fighting metal theft. Spurred by the rise in world prices, thieves are ripping copper and lead from railways and telephone networks, water and gas mains, churches and war memorials. Thames Water is just the latest big firm to turn to SmartWater. Network Rail is using its services in parts of the West Midlands, and metal theft is said to be falling there. Ecclesiastical Insurance insists that the 16,000 Anglican churches it covers use SmartWater and claims it has helped to secure convictions. If acquisitive crime really does rise along with unemployment, the forensic squad will be there waiting.