back to article New prison law will let UK mobile networks deploy IMSI catchers

The Prisons and Courts Bill, introduced to Parliament last week, will force UK mobile networks to deploy fake mobile phone masts around the outside of prisons to snoop on mobile phone users. Provisions in the new bill will allow the Justice Secretary to order networks to deploy so-called “IMSI catchers” to prevent, detect or …

  1. Sgt_Oddball Silver badge

    how about..

    Those who live near a prison? Would they end being asked all the time to account for their phones? (Armley jail in Leeds for example has a wall next to private houses) you'd have to be very careful to ensure it captures only phones inside the designated areas.

    1. Anonymous Coward
      Anonymous Coward

      Re: how about..

      Oh I wouldn't worry.

      After all, if you have nothing to hide then you have nothing to fear.*

      *biggest pile of verbal shite since the creation of the universe.

    2. Anonymous Coward
      Anonymous Coward

      Re: how about..

      Came on to ask the same thing, I work in prisons occasionally as part of my role and there are three nearby, two of which are literally inside residential areas. That's a lot of innocent people with their phones being tracked.

      I honestly can't see any reason for not blocking mobile signals in prison grounds - it is doable to within a few meters in most cases other than them using those mobiles to intercept information on crimes taking place outside prisons.

    3. kain preacher

      Re: how about..

      The solution is to use femcell

      1. Crazy Operations Guy

        Re: how about..

        "The solution is to use femcell"

        I've always wondered why they didn't just blanket jail and prisons in a fine mesh, then implement a femto-cell within the cage. Set it up so that during the connection process it brings up a message stating that the local network is being actively monitored. Maybe just inform the person through a text message that the phone owner would answer:

        "I consent, but check with me later",

        "I consent and don't ask again"

        "I don't consent, but ask again later", and

        "I do not consent, never try to allow my phone to associate again"

        With it being in a Faraday cage, people who do not consent to the monitoring aren't tracked and their phone just doesn't work while being able to track the phones of people who do consent. For people being held, they'd either have to consent to being tracked or to go without connectivity.

        1. Anonymous Coward
          Anonymous Coward

          Re: how about..

          Putting a fine mesh around the cells is all well and good, but what about when the cell door is open? Unless they keep it shut all the time the prisoner is inside, the signal will have a way out. They also might be able to get creative in finding a way to get a signal out, by snaking an antenna down the toilet into the plumbing vent. Or cutting a small hole in the wall through the mesh and covering it with a picture of Rita Hayworth.

          Plus what about prisoners using phones in the laundry, shower, exercise yard, etc.? Are you going to put a fine mesh screen over those areas, including the yard? I guess that would stop the problem of tossing drugs over the wall or dropping them in via drone...

          1. Anonymous Coward
            Anonymous Coward

            Re: how about..

            "Putting a fine mesh around the cells is all well and good, but what about when the cell door is open?"

            He didn't say per cell, he was talking about the cage (a Faraday Cage, see: being the entire prison. The outermost walls having the actual Faraday Cage properties and components. Hoisting a mast in the prison yard, or trying to stick an antenna outside of the outer wall will be trivial to spot and manage, AND random citizens will not have to have their radio transmissions searched and seized by the titheads. Go ahead and quietly accept this, and soon you'll have every government agency and their dogs monitoring you and deciding whether or not you are doing something they don't like, wherever you live, not just near prisons like the "test population" of people too poor to legally fight back.

            I have the NSA/CIA/DHS monitoring all my traffic "for my safety" and the FBI flying overhead with Stingray cellular spy "towers." In both cases they are not "cleaning the streets of terrorists," merely infringing further on the few rights that the citizens still cling to, and that they (FBI, et al) secretly oppose. This is NOT what the founding fathers had in mind. This is spying under the guise of the latest boogeyman (Russians, Muslims, etc) but the end result is my privacy is circumvented.

            What would happen if someone could engineer a super low-cost 2/3G fake celluar device that clogs up the works of these fake towers? Real tower? Pass. Fake tower? Keep asking for authorizations to DoS it, then flood the airwaves with fake traffic, or inspect the other devices, etc. Sure, it's illegal to setup a cell tower... I'm taking about fake devices, and hundreds of them for ~US$10 each.

            I'm looking at an online catalog and they have some GSM/GPRS and Arduino "Cellular Shields", but those are US$35 and US$70. There's got to be a cheaper way, like reusing old castaway phone, etc. Hack 'em, if they can't take a joke!

    4. Vagnerr

      Doesn't this already contravene premium rate call rules (in the UK at least)

      Yup and the Reading to Waterloo SWTrains line goes right past HMP Bronzefield, So I guess that's a good 50-100,000 mobiles pinging that on the way past everyday.

    5. Anonymous Coward

      Re: how about..

      Winson Green Prison in Birmingham.

      Surrounded by houses and very busy roads. Oh how about that bloody great hospital just round the corner?


    6. Danny 14 Silver badge

      Re: how about..

      HMP garth in Leyland is also next to the prison. I rented a house there for 9 months when I worked for british Leyland. You had some weird folks parking up nearby.

    7. JetSetJim Silver badge

      Re: how about..

      > you'd have to be very careful to ensure it captures only phones inside the designated areas

      Perhaps a directional antenna of some sorts is in order... Yes, there's a certain amount of RF leakage in all directions around a directional antenna, but in prisons with nice thick, high walls this is probably entirely manageable. Mount the antennas high up pointing in & slightly down. Muck around with transmit power so they don't overshoot the walls on the other side of the compound by enough to trigger any handover attempts from outside.

      All they need to do is make sure that their "fake" cells are the dominant signal inside the prison in most areas, and are not dominant outside the prison.

      As to the "mobile flagging up if encryption isn't enabled" - if the operator is deploying these "fake" cells, then they can be deployed in the operators domain, and so encryption needn't be disabled. All they need to do is to configure the cell to not actually provide any service, which is a doddle.

    8. 2+2=5 Silver badge

      Re: how about..

      > Those who live near a prison? Would they end being asked all the time to account for their phones?

      Unlikely - because after the first time, they'd be put onto an exception list. What's more of a concern is that criminals will start paying or coercing people who live near a prison to allow their name and address to be used as the registered address for a phone that has been smuggled in.

    9. phuzz Silver badge

      Re: how about..

      Sure, this is a terrible idea for all the prisons in the centre of cities, but it would work really well for Dartmoor.

      Mind you, the idea of a Faraday cage round the entire prison is a good one. Not only would it prevent prisoners from using mobiles, but it would also physically stop drones from being able to drop contraband in, and in the event that someone made a hole in the cage, the sudden influx of EM radiation from outside should provide a warning of a breach.

      If only it wasn't so impractical to do for an entire prison.

  2. Warm Braw Silver badge

    you'd have to be very careful

    But they wouldn't. Nice when you make the law, isn't it.

    1. big_D Silver badge

      Ah, now Brexit makes sense... No more goody-two-shoes sticking their oars in.

  3. Anonymous Coward
    Anonymous Coward


    Now lets campaign for a prison to be built next to the houses of parliament.

    Seriously though, why don't we just make Wales a prison. Theres no phone signal and plenty of hard bastards needing work that could be jailers.

    1. theModge

      Re: Ok...

      Now lets campaign for a prison to be built next to the houses of parliament.

      Undue expense and disruption. All locks for the house of parliament to be on the outside. Politicians can argue with each other until blue in the face, but can't get out to do any harm

    2. Anonymous Coward
      Anonymous Coward

      Re: Ok...

      Seriously though, why don't we just make Wales a prison.

      Probably because our lords and masters have already signed treaties against that sort of cruel punishment.

    3. TitterYeNot

      Re: Ok...

      "Seriously though, why don't we just make Wales a prison"

      No. We tried that with Australia and look what happened - Fosters and Rolf Harris...

      1. Pseudonymous Clown Art

        Re: Ok...

        "No. We tried that with Australia and look what happened - Fosters and Rolf Harris..."

        They half arsed their beer and sex offenders. Just like they half arse cricket and rugby.

        We have Tenents Super and Jimmy Savile.

        The only thing the aussies do better than the Brits is export droves of scrounging bar workers and backpackers.

        1. MrDamage

          Re: Ok...

          > "The only thing the aussies do better than the Brits is export droves of scrounging bar workers and backpackers."

          At least our backpacking bar workers know how to pour a bloody beer, have yet to meet a pom out here on holiday who has half a fucking clue on how it's done.

          At least we have our native wild life available to cut down the numbers of the useless bastards.

          I'll give it t you on the cricket comment, after all not that many aussies are interested in a sport where watching the grass grow on the field of play is more exciting than the game itself.

          1. Anonymous Coward
            Anonymous Coward

            Re: Ok...

            At least our backpacking bar workers know how to pour a bloody beer, have yet to meet a pom out here on holiday who has half a fucking clue on how it's done.

            In a spirit of Commonwealth camraderie, I'd like to ask how would you Aussies know how beer should be poured, when you don't even know what real beer is, of either ale or pilsener traditions?

  4. JimmyPage

    re:what about those who live near a prison?

    Who cares ?

    I get it *you* do, but - as you are finding out - unless you actually matter (i.e. can directly affect the chances of the next Tory general election victory) you can fuck off with your whinging.

    I expect a slew of downvotes, but in 2017, it's just calling it as it

    Is the comment on what the government cares what you think.---->

    1. Anonymous Coward
      Anonymous Coward

      Re: re:what about those who live near a prison?

      I suspect they will target the imsi's seen using the prisons signals that are never seen using any other mobile signals

  5. AndrueC Silver badge
    Big Brother

    Cool. I used to walk past HMP Birmingham several times a week during the summer when out for my lunchtime walk. Mind you - what's the range of these base stations? There's a fairly busy railway line that isn't that far away and quite a few houses as well.

  6. Richard Simpson

    Encryption aware phone?

    "Handsets are supposed to provide an on-screen notification when encryption has been disabled, but conformance to that detail is very rare indeed."

    Has anyone ever seen such a notification? More importantly, are there any phones where you can set a flag which means "If the base station asks for an unencrypted connection then the answer is always - No"?

    1. Anonymous Coward
      Anonymous Coward

      Re: Encryption aware phone?

      Once upon a time ages ago I had an ancient Ericsson T-whatever which was built like a brick. I guess (hope) it was a misconfigured base station, it displayed an exclamation mark next to the operator name. I had to look it up in the user manual to find out what it meant afterwards.

      Android doesn't show anything useful, I guess it's too busy showing useless notifications instead.

      If you restrict your phone to 3G or above you won't get caught as it relies on a 2G exploit (possibly).

    2. aaaa

      Re: Encryption aware phone?

      For iPhone - iOS 5 (and later) apparently - though as other posters have said - you need to disable 2G - because whilst 2G is 'encrypted' it's so weak it almost doesn't matter. And I think SMS is never encrypted.

  7. John Brown (no body) Silver badge

    The Met

    "The Metropolitan Police in particular has been operating IMSI catchers, along with a covert air wing run through a front company registered to an anonymous mailbox in South London, since at least 2011."

    That pretty much demonstrates that they know they are doing wrong and need the arms length "out sourcer" to pass the buck to when it comes to bite them.

    1. Anonymous Coward
      Anonymous Coward

      Re: The Met

      need the arms length "out sourcer" to pass the buck to when it comes to bite them

      When and why would any consequence come back to bite the Metropolitan Police, no matter what they do? FFS, Cressida Dick is now Metropolitan Police Commissioner (in addition to the Queen's Police Medal for "distinguished services") after her oh-so-brave armed cowboys held down an innocent and unarmed man and pumped him full of soft nosed bullets.

  8. Lee D Silver badge

    Is it still me that's of the opinion that if you need to track mobile phones in a prison, that the prisoners shouldn't be able to get hold of them anyway?

    Fixing entirely the wrong problem.

    Sure, this might catch a few (stupid) over-the-wall-throwers, jailbreaker assisters, etc. but they will smarten up quite quick and just leave their phones at home that day.

    If prisoners having phones is a problem, stop them getting phones.

    And if a dragnet like this is anything other than "there's a new phone on the site!" "Well, where did they get that from, trace the history and see if we can work it out", then you're really on the wrong side of the problem.

    If you can smuggle a phone, you can smuggle a knife or even a small bomb.

    1. JimmyPage
      Big Brother

      re: Fixing entirely the wrong problem.

      Depends on (a) what the problem is, and (b) what the *real* point of the fix is.

      So for (a): just whip up a mediasyteria campaign about <insert bogey man>. Be it child abuse. Child porn. Drugs. Cyber bullying. Whatever.

      then (b): draft some laws which are promoted as "the answer". Not too many questions from the supine press, and if you did (a) right, you will get any criticism silenced with a "friend of the paedos" type slur.

      NOTE: In Tory2017, you plan (b) *before* working on (a).

      All this will be enthusiastically cheered on by the masses who forgot the fairytale about the wicked Queen who was tricked into devising her own worst punishment.

      "Ah but" say the tabloid readers "that's only for criminals" - also forgetting a criminal is only what the (Tory) government says a criminal is.

    2. JetSetJim Silver badge

      You can smuggle a phone up your jacksie. Not entirely sure I'd like to try smuggling a knife that way - it's easier to make one when on the inside, I'd imagine.

  9. Anonymous Coward
    Anonymous Coward

    Here's a super idea to solve the problem,

    Stop letting them get smuggled in.

    I would say with ideas like this I should be in government but then again I'm not a massive cock womble.

    1. Blofeld's Cat Silver badge

      Er ...

      "... cock womble ..."

      I often wondered if Madame Cholet would be a hen womble with Orinoco and Tomsk being chick wombles.

  10. Anonymous Coward
    Anonymous Coward


    Fwiw, the last recorded flight of G-BVJT on was on 02/08/2015. doesn't show any recorded flights (possibly because of inbuilt date-limits on search).

    Seems possible that they're using a different aircraft now.

    1. Roj Blake

      Re: G-BVJT

      Or possibly that Flightradar24 has received a gagging order.

      1. Anonymous Coward
        Anonymous Coward

        Re: G-BVJT

        Flightradar24 is based in Sweden - dunno if they'd accept a gagging order from the UK.

        Would probably be easier to simply not broadcast their ADS-B data, as already seems to be the case for the police and military. Indeed, I was rather surprised that they actually were broadcasting on ADS-B.

        1. Anonymous Coward
          Anonymous Coward

          Re: G-BVJT

          I've seen aircraft belonging to Reconnaissance Ventures on FR24 and watched their recce orbits over other cities, but I've never seen a recce flight track of any kind over London on FR24. I've seen Voyagers, A400Ms, Tornados, Hawks and Apaches on FR24, but never the Defenders.

          1. Anonymous Coward
            Anonymous Coward

            Re: G-BVJT

            This is an old thread now, but if anyone's interested, right now on 9th March at 19:30 this aircraft is clearly visible and audible, orbiting over North London. It's not leaving a trace on FR24.

    2. Anonymous Coward
      Anonymous Coward

      Re: G-BVJT

      I live in North London, and since soon after 9/11 have watched twin-prop aircraft flying in large circles above the area at between 8,000 - 15,000 ft., above the airliners approaching Heathrow. At first they were RAF B/N Defenders, based at Northolt:

      Since then I've seen the Caravan II, and on occasion what I think was a Piper Seneca or similar. The Defender and Caravan are both turboprops, but the Seneca is a turbocharged piston. They all sound quite different.

      They're easy enough to hear if you're in a relatively quiet place and pay attention, but often quite hard to see, especially the camouflaged Defenders. All these aircraft were very active around the 2012 Olympics, but since then I've become gradually less aware of them. No doubt a good deal of ground infrastructure has been installed to take over this task since then.

      Am I bothered? Yes, but actually I'm more bothered by weirdy beardies.

  11. Sgt_Oddball Silver badge

    just realised..

    My phone can do WiFi calling. If the lags can get WiFi then this tool can be neatly gotten round (or use a voip service like Skype ect. ) then what? Legal calls to monitor voip calls?

  12. Simon Rockman

    WhatsApp does secure voice

    So anyone who wants to make a call that their mobe network can't and over to the police just needs one of the most popular apps around.

    There is a big difference between IMSI capture and listening to the call. And litening to a call from a plane where there are cell hand-off issues would be very hard.

    I often wonder how the secure phones (Black Phone, General Dynamics et Al) handle the MAC address. There is no point the phone bit staying under the radar if the WiFi is broadcasting an unique number.

  13. cantankerous swineherd Silver badge

    Android IMSI Catcher Detector is a thing

  14. Commswonk Silver badge

    Oh dear...

    From the article: The police, however, are slightly different in that they can go back to the network operator later and link the TIMSI to a real IMSI. That will generally link to a physical person, who might then have to explain what his/her phone was doing at the time in question.

    That will work extremely well if all the illegal phones in the prison are conveniently on contract or are registered PAYG. Somehow that seems rather unlikely.

    Given that many of the illegal phones may have been previously stolen from their rightful owners it becomes extremely important that any theft or loss is reported immediately so that any later illegal use can be shown to have taken place after the theft or loss. There is also a case that any phone and / or SIM that has been replaced should be destroyed so that it cannot go through a second hand chain and finish up being used for illegal purposes; that could all to easily come back to haunt the original totally innocent owner, and while proof of guilt is for the prosecution and the courts to establish just saying "it was lost / stolen / sold on" without being able to prove that statement could become a source of undeserved pain.

  15. adam 40

    It's not "TIMSI" it's "TMSI"....

    ... although it is pronounced "timsi".

    I like the sound of those "femcel"s, are they used by fembots perchance?

    1. Anonymous Coward
      Anonymous Coward

      Re: It's not "TIMSI" it's "TMSI"....

      I like the sound of those "femcel"s, are they used by fembots perchance?

      No - but those mascells are pretty much gagging for them..

  16. Anonymous Coward
    Anonymous Coward

    What about wireless signals?

    Are they blocking 2.4GHz or 5GHz? What's to stop residents providing directional Wireless to allow the prisoners to communicate confidentially via Internet? It would at-least remove the need for HMPS to spy on local residents mobiles :D

    1. Anonymous Coward
      Anonymous Coward

      Re: What about wireless signals?

      Won't work. The WiFi Detector Van would spot them!

      HAHA! j/k If they can't keep the inmates from getting cell phones, what's to stop the inmates from building and running their own satellite uplink, or point to point microwave ground relay station? Or a super-compute cluster made of bum-smuggled Raspberry Pi systems all running out of what appears to be a broken microwave oven? Or rooftop mounted, high-power, directional WiFi antennas that they use to break into neighboring, innocent networks and secretly steal their Netflix passwords so they can watch all the love and drama movies that would make their watch lists look all girly? The mind wanders, I mean wonders, it wonders. Keep it together, chaps!

  17. GruntyMcPugh Silver badge

    Install an app like Opensignal, and see if any 'new' towers pop up on your local map,.... might need to compare to results from a phone on a different network, I presume the fake masts will show up as servicing every network, rather than just on one network. Interestingly, there is a phone mast reported as being on the street opposite the local prison here,.....

  18. tedleaf

    El ref,seems to be a bit behind the times,the UK government has a whole fleet of com's interception and monitoring aircraft,come to sunny Watford and you can watch them taking off from RAF northolt everyday,we have at least 4 bn islanders that take it turns to float per London,24/7,that old caravan is used sometimes,but we also have some other twiin engine hobbies that are similar to the Cessna caravan but have massively extended wings(front to back) almost twice the size of "normal" wings..

    Northolt is a very intetestig field to watch,you never know what or who you are going to spot using it,half the real "vip's" that fly into the UK use it,saves them having to mix with hoi polio at public fields/airports...and is also very close to gif courses,which comes in handy for American presidents...

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