Billed as an "ultrasonic teenage deterrent," the Mosquito is claimed by manufacturers Compound Security to be "the most effective tool in our fight against antisocial behaviour."

Inventor Howard Stapleton said this would be the first time the Mosquito had been used in Sussex.

With an effective range of between 15 and 20 metres it relies on the medical phenomenon known as presbycusis or age-related hearing loss which begins at the age of 20 but is usually only thought to be significant to the elderly.

It makes it possible to generate a high frequency sound of 18 to 20 Hz that is audible only to teenagers.

The system, thought to be harmless even with long term use, was first used at a Spar shop in Barry, South Wales, where owner Robert Gough said: "Either someone has come along and wiped the troublemakers off the face of the earth or it's working."