Supermarket bosses have apologised to customers this week --after a high-pitched alarm only youths can hear made it impossible for some teens to shop at Eccleshall's new Co-op store. Parents told the Post their children had been forced to boycott the High Street shop, which opened in April this year, following the installation of a 'Mosquito' device. The ultra-sonic teenage deterrent emits a frequency, which although harmless, makes it extremely uncomfortable for those under the age of 20 to remain within a few metres of it. One parent told the Post: "My son, who's 20, came home the other day and said he couldn't shop there again because the alarm caused him so much pain in his ears. He said it was unbearable." Julie Potts is spokesperson for the Midlands Co-operative Society. She told the Post the Mosquito device had been installed to prevent youths congregating outside the store's doors. But she admitted it could have been left on too long and issued this apology: "We are sorry if the device was used for longer than was strictly necessary and we sincerely apologise for any inconvenience to any customers affected by this. "Our policy is that the Mosquito is only to be used when there is a problem with youngsters gathering around the entrance to our store causing problems for customers." She added: "Youngsters congregating and behaving in an anti-social manner around the entrance to stores is a real problem and we hope that our customers understand the installation of these devices is intended to minimise the likelihood of them being inconvenienced by such behaviour." The system, first introduced in America, is backed by police and has become widespread in the battle against teenage anti-social behaviour. A medical phenomenon known as presbycusis, or age-related hearing loss, which begins after the age of 20, is the key to the alarm's effectiveness. The condition first affects the highest frequencies the human ear can detect and it is possible to generate a high frequency sound that is only audible to teenagers. | 
