“How do I go about suing the police?” These were my caller’s first words, and he gets full marks for getting my attention. Like a number of retailers, he had been driven to distraction by noisy teenage hordes gathering outside the store. The worry for anyone in this situation is that it could escalate into violence, or at the very least put off customers from entering the threatening space that surrounds the store. Both of these applied in this case to my caller, who has requested anonymity because he hadn’t called to have his story told – he really wanted to sue.

He was so fed up with the unruly behaviour of the kids gathering outside his store and the police’s lack of force in controlling it, responding to it, or preventing it, that he was seriously considering this extreme legal action.

When he rang on December 1, 2005, things had snowballed. During that week he had been barricaded inside his store while kids, off school because of bad weather, aimed snowballs not just at the exterior but also inside the store. The same week he had also been confronted and threatened by a violent man who simply refused to leave, saying: “Make me”. He is frequently alone behind the counter, and his neighbours on both sides are OAPs (one of whom has already has his telegram from the Queen).

The flat over the shop is empty, the windows have been broken one by one, and many of the store windows are now also boarded up. The owner cannot team up with others in the parade because there is no parade. He trades solo opposite a small park in a location that once upon a time would have been considered a great opportunity to make a catchment ‘killing’. Now the park is a sordid little place, where syringes are handed round and beer cans dumped.

We used to recommend to retailers plagued by teenagers that they play classical music. It doesn’t soothe the savage breast; kids just find it uncool and go and hang about elsewhere. But in this case a lot of the damage occurs late at night after the shop is shut.

Enter inventor Howard Stapleton of Compound Security Systems in Cambridgeshire, for whom things have also snowballed – in a good way. Stapleton has invented a machine that makes an ear-piercing noise that only teenagers can hear (think dog whistle and you’ll quickly get a handle on this). Apparently, hearing levels change with age. He sent out a press release about the product, including one to our sister paper The Grocer, and suddenly the net widened. “More than 6,000 people have found our website since that first mention in The Grocer,” Howard tells me.

He says that one of the first retailers to try out the alarm, which is called Mosquito, was Robert Gough, who runs a Spar in Barry, South Wales. After using the device, the teenage terrors vanished. Robert says the kids tell him it “does their head in”, and some asked what it was for. Very enterprisingly, he tells them it’s to keep birds away in case of Avian Flu.

The unit costs £495 and the security cage is another £35, but you can get the cage for free if you mention Convenience Store magazine. Stapleton’s invention is far cheaper than getting a lawyer on the police’s case. To order, go to the very easy-to-navigate website www.compoundsecurity.co.uk.