Anyone who knows me will tell you that I don't do public transport - at least not when I can avoid it, writes Andrew Everard. And that means I'm spared the annoyance of having to listen to someone else's music, albeit at 'tssska, tssska' level, leaking from their iPod headphones beside me. At least I thought I'd escaped others' music until I was stuck in traffic the other evening, inching along and listening to the Radio 4 Six O'Clock News. Straight across a report about some aspect of Middle East policy came a bouncy pop tune, fading in until it completely obscured the news. Strange – and even stranger was that as the jam moved forward, it faded away again, allowing the dulcet Radio 4 tones back through, then returned to swamp the report once more. Now it was a piece about dangerous dogs, mixed with bass-heavy dance music. It took me a while to work out what was going on: a look in the rear-view mirror revealed a face in the car behind lit with the tell-tale glow of an iPod display, clearly being fed to that vehicle's radio with one of the newly legal in-car transmitters, which plug into the car lighter socket and the music player, and transmit the user's music on a frequency suitable for the radio. Or anyone else's radio, it seems. As I moved forward the sound faded; as the car behnd closed up again, the music came back. Maybe I'm just infortunate in that my car's aerial is at the rear, or maybe these transmitters, which can now be bought for as little as £30, are a bit too powerful for their own good. But a whole new world of annoyance is opening up as the use of these devices will inevitably become widespread. 'Tssska, tssska' on the tube, it seems, was only the beginning...

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