London: DNA testing has become the latest weapon of companies trying to flush out pranksters among staff.

Last month, the head of an IT company in Farnham, Surrey, told 80 employees that they would have to undergo DNA tests to discover who was responsible for chewing gum that got stuck on a director’s trousers. Although the firm later claimed that the threat was a joke, a laboratory in Norwich said that it was doing increasing amounts of such work.

Despite criticism from civil liberties activists, Anglia DNA has been asked by an estate agency to conduct tests on bed sheets from a vacant house because directors believed that an employee was secretly sleeping there. The laboratory has also been asked to solve the mystery of another firm’s kettle, which someone kept filling with urine, and someone who was leaving even less savoury deposits in a third company’s locker room.

So far, the act of getting the DNA profiles from the offending materials by the laboratory, which primarily concentrates on paternity cases, has been enough to end the dubious practices.

Dr Thomas Haizel, the head of Anglia DNA, said: “If people do not misbehave at work, then they have nothing to fear. We are helping to prevent injustice at work by identifying the real culprits which prevents innocent workers from being falsely accused of some form of malpractice.”