Commuters shouting into their mobiles? Just jam 'em

No such questions are suggested at PhoneJammer where the devices are sold. Instead, it explains how useful its products are - and at prices around £2,000 - for major projects like preventing phone calls in cinemas and theatres and churches:

Introducing the ultra high power phone jammer, the most sophisticated digital cell phone jammer of its class, with tough die-cast aluminium casing and dual inter cooler, ideal for large to hall type rooms or outdoor locations (high gain base station type antenna supplied).

I'm not saying such devices aren't available. Actually, I wouldn't even try to pretend I think they aren't in use. I happen to know a cinema not far from here where, mysteriously, car alarms won't work in the car park behind the theatres, and while they do ask patrons to switch their phones off, I've yet to hear one ring. Perhaps the patrons are all saintly?

Perhaps not. Our silent but deadly social villain tells a lovely story about how he arrived at a party in an unnamed location, furious about having his train journey ruined by someone talking... (why?) and was furtively led to one side:

'You need a jammer.' With a nod and a wink, I followed the dapper man to the outer edges of the party and he began to explain. He commutes from somewhere Midlands-ish to somewhere Birmingham-ish. When an annoying fellow commuter begins to prattle, he simply flicks a switch and the prattling ceases.

How seriously should we take this James Bond narrative?

Well, in one sense, entirely seriously. The devices do exist; and prices don't have to be measured in the thousands, or even the hundreds. There are toys which cost £50 ($100) and will knock out phone conversations within five yards. And you can order them.

Which leads us to the mystery: why Rudd made such a big fuss about the problems of finding suppliers. It's really not a problem and Google will point you at dozens of suppliers - but the humourist (perhaps) made him go on about how he broke the unspoken code of jammers, by asking to speak on the record. And after that, he laments, nobody would tell him anything. Including where to find one...

OK, back to the spy review, and maybe we can find what the real problem is. The real problem might just be "does it work?"

That's the problem with buying illegal products. You send your credit card or PayPal details; and you get a little black box in the post. Written on the side is "Phone Jammer" and inside the box is a Japlish instruction manual which says: "Press button B" and, well, that's that.

You press button B. The conversation which is so irritating your sensitive little soul, continues unabated. Your jammer: is it under powered? not close enough? or... horrible thought! - have you been taken?

There's not a lot you can do if you have been, is there? What are you going to try - complain to Ofcom? I don't think so... Trading Standards? "I've bought this illegal product which is impossible to test without breaking the law, and I suspect it doesn't work..."? No, I think best not.

And, of course, there's the final ignominious possibility... that your jammer works just fine - but that the loud-mouthed person on the train is, in fact, an unemployed PR bunny who can't afford a real mobile phone right now, and is actually just making loud noises to impress fellow travellers.

Oh, yes, it does happen. You can actually buy dummy phones for that purpose. Just don't ask for your money back if they don't work, OK, yah? ®