A Welsh invention which claims to repel rowdy teenage ne'er-do-wells while leaving lawabiding fortysomethings and septuagenarian war heroes to go about their business unmolested has been creating a bit of a stir in the UK and international press this week.

Howard Stapleton's "Mosquito" emits an ultrasonic sound which can be heard by most kids and teenagers but is inaudible to the majority of adults over 30 due to the inevitable deterioration of hearing with age.

Field tests at a grocery store in Barry, South Wales, and a shop in Stapleton's home town of Merthyr Tydfil have proved successful, with rowdy yobs driven from the premises.

The future looks bright for the Mosquito, with its inventor admitting to Reuters: "All I'm getting is pats on the back." And no wonder. ®