Given that -- as I understand it -- most stolen mobile phones end up abroad, this isn't something that can be dealt with on a country-by-country basis. Presumably any code that's sent by a UK network to shut down a handset can be over-ridden by someone reflashing the phone when it arrives in Russia / Africa / insert-bad-country-of-choice.

The only thing I can see that could do the trick would be something that physically damages the circuitry. Maybe phones could all be fitted with small explosive devices which could be activated once the local chavs have got hold of them. Just don't tell the yanks though, they're paranoid enough about what goes onto planes as it is!

A lot of theft is motivated simply by the desire to annoy someone. The thief doesn't care whether or not the stolen property is of any use to them -- they only care about you not having it.

Someone thinking like that isn't going to be in the slightest bit deterred by a mobile phone that renders itself inoperative once it's been reported stolen.

They might, however, be turned on by the idea of remotely deactivating other people's mobile phones without having to go to the effort of stealing them first.

Um, doesn't this also mean that the police can get ANY phone to report its position? So if they suspect you of possibly doing a crime in the future (hasn't el Reg already reported on this?), they can watch your every move (tie the mobile to surveillance cameras).

How far behind can the FBI be?

The current system where a phones serial number (IMEI) is banned has an interesting history.

At first only a couple of networks supported IMEI blacklisting and the rest said it would be impossible for them to implement. Nevertheless they managed it soon afterwards after pressure was applied.

The current system has an oft exploited loophole. The original owner of a phone sells it. After the recipient checks all is OK (and giving positive feedback on Ebay) the first owner reports it stolen claims on insurance and the poor sod who has bought it gets their phone deactivated.

Getting such a phone reactivated is all but impossible.

The networks could transfer the ownership of phones:so only the new owner could report it stolen but they wont.

It is against their best interests to do so because it spreads FUD about the second hand phone market.

Instead it is often stated that it is never safe to buy a second hand phone.

The Register figured out the solution to this problem years ago. Make them big, make them heavy, make them ugly, make them sound like crap and plaster a big logo on the front. If this doesn't do it, toss on a 18" whippy antenna, that'll do it. Thanks Simon for solving society's problems before they occur.

Russia? Africa? How about Jersey! As a youth I used to work in a mobile phone shop, one of my collegues had a racket buying "second hand" phones no-questions-asked and selling them to shop in Jersey.

As Jersey doesn't (or at least didn't) subscribe to the UK's IMEA blocking scheme the phones could be used no problems.

"The networks could transfer the ownership of phones:so only the new owner could report it stolen but they wont."

What if you buy a phone sim-free? Many people do.

"it's almost always (69 per cent)"

69% isn't "almost always".

Thieves usually switch off cell phones immediately, thus rendering any signal-to-disable technology utterly useless.

It is alluring to think that phones may be thief-proofed by designing them so that they are deactivated by default. Only those that are authenticated and authorised would receive a regular network signal to enable them.

Perfect isn't it?

The only drawback of this system is that we have it already, and it clearly does not work!

GSM telephony authenticates the hardware via the serial number of the phone (IMEI), which has been made "hard" to change. The subscriber is authenticated via the chip-and-pin of the SIM card (IMSI).

There is little economic incentive for criminals to crack GSM SIM cards. (For CDMA phones where there is no removable subscriber card the situation is different and phone id. cloning is a popular criminal activity.)

The weakness of IMEI protection is that the phone makers have tended to secure other settings using the same technology. (Things like network locking and the nobbling of features.) In a number of countries it is legal for a third party to change these for the legitimate owner of a handset. Since the same technology secures the IMEI, once the protection can be circumvented for legal reasons, the IMEI is accessible too. Worse yet, not all countries have made it illegal to change serial numbers.

In practice the IMEI can readily be changed in seconds by criminals with little technical knowledge, using a PC with the right connector for the phone and suitable software that can be obtained via the Internet. The reprogrammed phone is back on the street with its new serial number in minutes, often before the original serial number has been blacklisted.

How would the proposals change any of this?

"The UK Home Office yesterday met with handset manufacturers..."

No, it didn't.. because there's no such thing as the "the UK Home Office". And I don't even mean that the Home Office **for England & Wales** had its structure changed as a consequence of John Reid's reforms...

... I mean that the UK doesn't have a "Home Office". There certainly isn't one for Scotland, and I'm pretty sure that Northern Ireland doesn't have one either... :-(

Shutting down a phone once it hase been stolen is possible. Using appropiate techniques it is possible to make it impossible to reprogram a microprocessor. Also there is no reason why a shutdown comamnd could not permantly dissable the phone, that should be relatively mundane.

However the only problem: is there a need for a solution ?

I seem to remember that the old analogue cell phones used OTP chips to store a unique identification number, instead of using a replacable SIM. You could replace the chip containing the unique number but it was not worth the effort - sourcing the right chip and then replacing it without frying the rest of the phone is a lot harder than flashing a phone using a suitable cable.

However, the manufacturers are unlikely to want to return to the complication of making the phones unique at manufacture, especially as theft-replacement probably boosts their sales.

"Um, doesn't this also mean that the police can get ANY phone to report its position? So if they suspect you of possibly doing a crime in the future (hasn't el Reg already reported on this?), they can watch your every move (tie the mobile to surveillance cameras).

How far behind can the FBI be?"

They already can do this, just not very accurately. The police can tell which cell tower your mobile phone is connected to. In large cities where there are a lot of mobile cells, they could certainly work out what street you're on, and track your phone changing mast as you move, giving an indication of your direction.

Talking amongst my friends none of us has ever had a mobile phone stolen... lost, run over, dropped overboard, yes.. but stolen, no.

I had heard a rumour that a lot of "thefts" were really just a way of getting a new phone on the insurance for free.... report it to the police, get a crime number, give that info to your phone company and bingo... one nice shiny new phone.

"In practice the IMEI can readily be changed in seconds by criminals with little technical knowledge, using a PC with the right connector for the phone and suitable software that can be obtained via the Internet. The reprogrammed phone is back on the street with its new serial number in minutes, often before the original serial number has been blacklisted."

Andrew J Winks: - Changing the IMEI humber is no where near that simple and hasn't been for a good few years. It used to just be a case of connecting the phone up to a computer and as you say, using easily downloaded software you could change the IMEI number. The IMEI number is no longer stored in the general firmware area (where you can set network locks, or flash the phone to remove operator specific software builds) but is now on a seperate write once chip, the only option is to unsolder that chip, replace it with a new blank one and program on a 'safe' IMEI number. Its not a simple operation and takes a fairly sofistacted setup with someone that knows what they're doing. I know this has been the case for Nokia, Samsung and Ericson phones for at least 3 years now.

What about second hand phones?

Its a booming industry for ebay, and second hand companies like cex.

Even if you check the phones imei out on checkmend

http://www.recipero.com/recipero/products/checkmend/

and it checks out to be fine, after it gets blocked you have zero recourse.

With companies like cex you are covered, but what about ebay, gumtree & loot?

For the uk, the only way to safeguard buying a second hand phone and not ending up with a blocked handset would be for the government to introduce some kind of transfer of ownership document.

Like a car log book this could be in 2 parts, one for the new owner to send off and one for the old owner to send off.

This could help everyone.

This way the phone can be registered to the new owner, if the previous owner then reports is lost or stolen to try and blag one on the insurance the networks can then claim any outstanding finance from them.

Doing this would be very unattractive to criminals trying to sell the old phones in the uk.

Lets face it, countries like Africa and most of the 3rd world will never take the uk's blocked imei database on, there would be a riot as most of the phones in Africa would stop working.

the networks can only win from this, especially as most of these phones are used by kids for prepay.

Martin Blunden is correct in stating that IMEIs stored in write-once memory cannot be updated, other than by replacing the chip.

That is being circumvented.

The latest wheeze is to rewrite the accessible copies of the IMEI and then to flash the phone software so it merely ignores the last, unchanged copy of the IMEI on the write-once device. The new IMEI is supplied by the phone whenever it is challenged.

If one is to believe the claims of the flashing-software vendors, there is scarcely a phone that cannot be nobbled.

The readily availability of such software indicates the extent to which there is an illegal demand, since there is no legitimate reason for changing a phone serial number.

It is still done just by attaching the mobile to a PC.

The only reason i know a little about this is that my parents used to own a secondhand electrical shop. We very rarely used to buy mobiles due to all the above problems, of not knowing if they were going to be cut off or if they were legitimate. (We always took I.D. for all stuff we bought, liaised with police for up to date stolen good's lists and if someone came in that was suspect we'd pass CCTV footage onto the police etc, My mother was a very honest person)

There was a dodgy shop in the same town that got busted for buying in hundreds of stolen phones and changing the IMEI numbers, a police officer told us all about the opertation and how they wen't about it. (unsoldering the chips etc)

We closed the shop last year as there's very little money in secondhand electrical goods, 4 years ago we could sell a dvd player for £60-80 (Sony, Panasonic etc) and make £20 on it, end of last year we were selling cheap arse dvd players (Technika, Alba, AudioStar) for £12 with a remote, and £5 without which we're only making at most £4-5 on, cheaper than the actual discs.