Concert halls, cinemas and even restaurants are banning the use of mobile phones, but the Japanese have gone one step further, selling jamming devices which knock them out of service. One such device, called a Wave Wall, is just the size of a cigarette packet but can knock out all mobiles within a radius of 20 feet by transmitting signals at their frequency. Reports say about 6,000 of the $480 devices have been sold in the past year, and the government has restricted their use to theatres or concert halls, where they can be mounted along the walls to jam all phones within the building.

But Irish restaurant-goers and theatre and cinema buffs who cringe at the sound of mobiles will have to suffer on, as enquiries by the Margin to the telecommunications regulator's office reveal such devices could not be used here without a licence. Too bad, but too bad for hotel owners too, who would love any device which could get their business customers off their mobiles and back onto the lucrative room phones, which have long been a big money earner.