The Children's Commissioner for England has joined civil liberties campaigners in a call for a ban on a device which disperses young people by emitting a high-pitched sound.The gadget, known as the Mosquito, exploits young people's ability to hear very high frequencies, a power which declines once they reach their 20s.Campaigners say an estimated 3,500 of the devices are in use in England to disperse children and young people in areas such as parks, shopping centres and around shops.Launching the "Buzz Off" campaign, Children's Commissioner Sir Al Aynsley-Green said the devices were indiscriminate and created a divide between young and old.He said: "I have spoken to many children and young people from all over England who have been deeply affected by ultra-sonic teenage deterrents."These devices are indiscriminate and target all children and young people, including babies, regardless of whether they are behaving or misbehaving."The Mosquito was invented by Howard Stapleton, from Merthyr Tydfil, South Wales, and is manufactured by Compound Security Systems.Shami Chakrabarti, director of the human rights group Liberty, said: "Imagine the outcry if a device was introduced that caused blanket discomfort to people of one race or gender, rather than to our kids."The Mosquito has no place in a country that values its children and seeks to instil them with dignity and respect."© Independent Television News Limited 2008. All rights reserved.