 Thank you very much everybody. So as I said, I'm going to talk about Railway signaling in the UK and I'm going to talk about this from the perspective of learning from accidents It's often said that safety regulations in in most industries are written in blood Because they're all based on the accidents that have happened that have caused injuries or deaths And we're going to look a little bit about how that's influenced the development of UK railway signaling So just a whiz through a few little bits to begin with This is the inside of a train Cab where the driver sits you'll notice there's no steering wheel So for those of you who hadn't realized railways run on rails. So I Said but in this audience most people know that be be surprised how many people in the general public don't realize that So signalers Do multiple things of getting trains where they should go and getting them there safely and To control where trains go they use points which are bits of movable rail So here you can see that you can go off to the left or you can go straight ahead and the way this works You can see in this little animation here You've got those two bits moving in the middle of the track and you can either go straight ahead or to the right or Straight ahead or to the right So as I said the purpose of signaling is getting trains where they should be going There's no point if the train going to London actually ends up in Birmingham instead But also getting them there safely in one piece at the right time With no accidents and no no safety incidents But I guess the first question is do we really need a signal or at all and early railways didn't have signals They were very simple railways. They were very small railways. They were very slow railways So if you don't have many trains, they're not really likely to very likely to hit each other And if they're going really slowly then if they do hit each other, they're not going to cause any damage So maybe you don't need a signaler and if you're going to choose where to go The driver just slows down when he gets to a set of points gets out and pulls a lever that looks a bit like this And then gets back in the cab and carries on his journey But when we started having into city railways that started carrying more people at faster speeds We really started to need signaling and the first of these railways in the world was the Liverpool and Manchester Railway Which opened in 1830 and in those days They had people who took dual roles of doing security on the railway and doing signaling And they were policemen basically and they were known as Bobbies and you'll still hear signalmen on the railways today referred to as Bobbies And they were spaced every mile along the track And they gave simple signals to the trains with their arms or later on with red and green flags And they had simple levers by the track They could pull for the points just to stop the driver having to get out and do it themselves And these were some of the early sort of signals that were then used when they moved from Flags and arm signals to actually fix signals These are early forms of semaphore signals which look just like a flag stuck out or an arm stuck out And you can see here on the left. We've got the danger position is it sticking out horizontally? Caution so warning you you might need to stop soon is Diagonally down and all clear is where it's hidden inside the post of the signal And this is kind of what these things looked like you'd have a signal box with the signals mounted directly Above the signal box and a little man in the signal box pulling levers to control those signals Now this takes us on to our first accident now at this stage in railway history I could have picked any number of accidents because there were loads of accidents in those days and loads and loads of people Got seriously injured or died But this one is what I picked Abbott's ripped and on the east coast mainline 1876 13 people died about 50 people were injured and Basically, the problem was that you were using the absence of something to say that it was safe to continue So you were saying here if you can't see the signal because it's hidden inside the post Then that's great carry on drive at full speed That's fine until the signal fails in some way like in this case it froze inside the post and couldn't come out So the signal froze at proceed and the and the drivers carried on and there was a crash So after this they moved into different types of semaphore signalling Keeping the signals at danger all the time and only clearing them when they needed to for a train And also various other things like like better breaks But I mentioned about how they use these signals But how did they know how did the signal and know whether to set the signal to stop or go? Well in these days they use time interval work Which is exactly what it sounds like count how long it was since the last train And if it's been less than 10 minutes stop the next train if it's been kind of less than 20 minutes Proceed at caution if it's been more than 20 minutes off you go full speed That's fine until a train breaks down somewhere and the train behind is at least 20 minutes behind it But catches it up and goes straight into the back of it and there were lots and lots of accidents with this It was not fail safe in the slightest And I think that really moved this on to the next stage of railway signalling was better communication The electric telegraph was developed in the early 1800s It sent pulses down a wire of electricity which is used to move a needle This could be done in various ways it could make a little bell go ding or it could point to different Letters on a display you could send messages that way Famously in 1845 it was used to catch a murderer by sending a message from London Paddington station saying The murderers just got on to this carriage of this train Down to the next station and then the police got on at the next station and arrested them And this could also be used for signalling. So here you've got a Set of railway tracks on the bottom there with four different signal boxes one two three and four When the train the orange train comes up to the second signal box It's going to be given a red signal because the blue train is still in between Signal box two and signal box three But as soon as it goes past signal box three Signal box three can send a message back to signal box two saying the train's gone past me now The section between you and me is now empty of trains. You can let your train go And that's what these areas were known as the sections between signal boxes are called block sections and they developed a method called Absolute block where the rule was there was absolutely only one train in each block section at a time And they did this by signal boxes sending messages to each other on the telegraph system Saying hello, I want a train to come into this section. Is it clear? Oh, yes, it is clear I'll accept it and then when the train actually went into the section There'll be a message saying the train has entered the section and then a little one later on saying the train has now left the section And along with this they had a set of of new style semaphore signals and Distant signals and home signals or stop signals stop signals are what they sound like it tells you whether you can stop or go Distant signals give you a caution They warn you that the next signal is going to be a stop signal and that's because Trains can take a long time to slow down They go very fast and they're steel way wheels on a steel track their stopping distance is quite significant So they have to slow down in advance to be able to stop at a stop signal a Minor issue Which is still not fully been resolved with the semaphore signals was that everyone agreed that the signal sticking straight out meant stop But no one could agree on whether sticking it down or up meant go And so you have lower quadrant and upper quadrant semaphore signals and you still have those in the UK sometimes even in the same area different ways of saying go and So around this time you've developed a better signal box These are just a few examples of different sorts of signal boxes from different eras But you know you'll all have seen these that sort of heritage railways and on the mainline railway as well Inside the signal box you'd have a big lever frame We controlled all the signals and here you can see the levers are all painted in different colors And there's a standard set of colors So the red signals are these stop signals you'll almost certainly find those are most of the levers in the frame The yellow signals are these distant levers that give you a warning that the next signal is going to be red Black is for points blue is for point locks You really don't want your points to move when a train's going over them because that would derail the train So you have an extra little lever that puts a special locking bar into the points and then any white ones a spare And you can also see this shelf above the levers with various indicators on it and Various other instruments on which I'll come back to in a moment But if we just first of all look at a signaling diagram For one of these mechanical signal boxes. This is Yarmouth South Town You can see there's lots of different tracks at the station You can see just about we can zoom in a bit more You can see the individual signals and the individual points and every signal and every point on this diagram has a number Like there's a signal 60 and a shunting disc 17 and a point 34 That's the number of the lever that you pull to operate that particular bit of equipment Well, how did they operate them? Well, it was entirely mechanical. They used rods and wires So for signals there was a wire that went around lots of pulleys and eventually pulled down on the arm on the signal and moved it to a different location and For points because they needed to move in both directions in a slightly different way They had rods, but again, they had lots of couplings on the rods to make this work That meant that you couldn't operate things very far away So the rule was that a mile away you could operate for signals, but only 350 yards away for points So that meant you had to have loads and loads of signal boxes because every time you had a set of points If it was more than 350 yards from another set of points, you needed another signal box to control it So this is a map of Digcot Near Oxford near Oxford just south of Oxford If any of you came to the train came by train to emf from London You'd have gone past Digcot on the train before you got up to Worcester and then led me to come here and This map shows about five miles Across and you can see there are seven signal boxes within those five miles There's a couple of ones at the end Milton and Morton cutting and then you've got about four signal boxes all around the junctions and the stations the station in the middle of Digcot and This was very expensive because these signal boxes had to be manned by qualified trained competent signalmen And they had to be monitored had to be manned some of them 24-7 some of them slightly less time And we'll come to that in a moment as to how the railway tried to get around that later on There's also a lot of interlocking of these levers. So this means that you can't set up Bad routes you can't set up a train to come one direction and a train to come the other direction straight into it Or you can't Put your stop signal to stop without putting your distance signal to caution to warn the driver that your stop signal is going to be Stop and so on and this was all done entirely mechanically again lots of levers underneath the levers lots of rods that interlocked With each other had little notches cut out of them. It's basically a Victorian style mechanical computer Further communication they used block Bell. So this was using the telegraph But it just rang a little bell whenever there was a pulse on the wire They'd have different shaped bells for different communications to different signal boxes So you could tell immediately from the bell Which signal box was calling you and they'd have these bell codes. So ding would be call attention. Come on I'm trying to talk to you listen up Ding ding ding ding three one would be is the line clear for a train and lots of other things like six bells in a row was Obstruction danger, which you never wanted to hear And also linked to the telegraph system. They would have block instruments Which were used to set up a display on in both signal boxes showing whether there was a train on the line or not and This combination of lock-and-block the idea of absolute block signaling and this interlocking was Mandated by the regulation of railways act in 1889 and I've got a very quick video that hopefully you're going to hear Just to show you what this is like. This is from Exeter West, which is a preserved signal box up in their crew So you can see here pulling the lever so you Unlock the lever at the back by putting the little trigger and then pull it He's then putting some of these back That's called attention so he responds with one bell That's a particular code He then sets his block instrument sends a code back and then goes back and pulls more levers And this is what a signalman would do all day Now the bit that some of you won't be aware of and will probably be quite surprised about is that this exact system that was regulated in 1889 is still in use today on mainline railways in the UK not all of them But in some places this is an example of semaphore signals at Worcestershire uphill station again if you came through Worcester came up from London through Worcester to Leadbury to get here by train you would have gone past that This is the the local area of railways In fact, you can see where you are near Leadbury here going up to Worcester and up towards droid Which all of the signals in this whole local area here are controlled by semaphore signal What signals from mechanical signal boxes using absolute block signaling all the same sort of things that were done in the 1800s just for a bit of local flavor if you did come by train and get off at Leadbury You'll have seen the Leadbury signal box there at the end of the platform This is what it looks like inside Leadbury used to have lots of sidings and an extra junction So there's lots of white levers that would have been used for those but are now not in use So they're painted white, but you can see the red levers black levers for some points a yellow lever in the in the end for a distance And one nice little thing about Leadbury signal box One of the things you have to do as a signal man is check that your signals are showing the right display And at Leadbury they couldn't see the signals because the footbridge got in the way So they just cut a little hole in the footbridge And so they've got a window in the footbridge lined up perfectly So the signal man standing in his signal box can check the signal at the other end of the platform to make sure it's showing the right thing Just for a slightly more impressive view. This is Worcester shrub hill station signal box Again, if you came to Worcester your train would have been controlled by this signal box This has 80 levers and very few of them are marked as spare now There's a lot of a lot of junctions and things in the shrub hill area and these are all Used very very regularly So we've got a way of controlling the signals But we also need to know a bit about where the train is because at the moment We know it's somewhere in the section between the last signal box and our signal box But we don't know exactly where and maybe we need to know maybe it might be sitting at a signal waiting for us to make It green or it's broken down somewhere or it's sitting on some points and we can't move those points because if we derail the train So we want to know where it is Well one way we can do that is just to look out at the window And that's why if signal boxes are built up on the first floor and they have big windows So you can see the trains of course that gets a bit difficult at night time in fog in falling snow and so on So there's another thing which is a rule rule 55 of the original rule book of the railways saying basically if your train stopped And you've been stopped for a few minutes. You have to send your fireman out of your train Up to the signal box to say hello signalman. I am standing at such and such a signal. Don't forget me and they would actually have to sign the train register a book in the in the signal box to say they'd come and The signal would have to put something in place to make sure he remembered that train was there And that could be something like this a lever collar You can see just circled in blue on the left picture a bit of wood on the back of one of the levers That makes it impossible to pull the lever or to pull the lever You just take the wood off again But the logic there is that by taking the wood off again, you're thinking huh? Why did I put this wood here? Is this reminding me of something important? Oh, yeah I probably shouldn't pull this lever because there's a train in the way or whatever Unfortunately accidents can still happen and the worst railway accident in the UK was at Quintin's Hill Negretna Green in Scotland. This was during the First World War And one of the trains involved contains a lot of troops going down to Liverpool To ship out for the for the First World War and it killed over 200 people And this was what the railway looked like at Quintin's Hill The little pink box at the top is the signal box and they had a double track railway going to Glasgow and Carlisle And they had loops on either side sort of sidings to put slower trains in So first of all, you've got the local train comes up on the main line Now what's he gonna do with it at this point the train the local train needs to stop somewhere for a while But there's no space in the loop on that side because another train is already there because there were loads of extra trains because of the war So he reverses it on to the other line now That's you know, not maybe what you would do every day, but it's perfectly safe And he then has another train come down and puts that in the loop. That's that that black train at the top That's cold and empty coal wagons But then unfortunately he then clears the signals for a troop train to come down the main line straight into that and Then unfortunately what then happens is what happens in lots of railway accidents Which is that the accident on one line causes debris to spread across the other line And a train comes down the other line and crashes into the debris Now why did this happen? Well, basically the signal when forgot about that orange train Now just to make this even more ironic that orange train was the train that he had travelled to the signal box on That morning and it got out when it was stopped outside the signal box, but he still forgot about it And the driver did do rule 55, but the signal man hadn't used a lever collar and the driver didn't check that There were a lot of other things going on. There was shift change irregularities Someone was covering for someone when they shouldn't have been someone didn't sign the register properly Other people were in the box who shouldn't have beaten but in the end There was no way for the signal man to know that the train was there and he forgot it was So after Quintin still a little bit before but also particularly afterwards there was a development in train detection technologies principally track circuits so the way this works is you take some kind of power source a battery or some other power source and you Feed electricity into the two rails of the track And then at the other end you get the electricity coming out of the track and you put it into a relay a signaling relay And so when there's no train on the track The electricity goes all the way through the track out the other end to the relay and you mark the signal as green Or you say there's no train there however, if you put a Set of wheels on the train these wheels are metal They've got a metal axle on them connecting them So they short circuit the electricity going through the track and rather than going right to the other end of the Track it gets short-circuited and goes back to the battery So in that case the relay doesn't get any power and that means that a train must be on that section of track Now the brilliant thing about this is it's fail safe It's if the track if the signal if the relay doesn't get any power then there's a train there So if the battery fails you just think there's a train there when there isn't which is far better than thinking There isn't a train there when there actually is So this was used in various ways It could be interlocked with the points and signals by doing some very basic Electromagnet work with the with the levers and do things like stop a set of points being moved while the train is is going over them And other things like you can't clear a set of signals If there's a train in the way that all that kind of stuff that would have solved Quintin cell And you can see here what the diagram would look like above a signal box these little black lozenges there are little lights that light up Red when the track circuit is occupied and this was installed mostly in the 1900s really This also is a slight diversion is why it leaves on the line are a great problem for railways Because leaves on the line insulates The wheels from the track so if your wheels are insulated from the track They won't short circuit the track and it will look like there isn't a train there when there actually is and They also reduce the grip and make it harder to stop So you've got two problems with that Which is why network rail spend a lot of money on things like railhead treatment trains We go around blasting sand and water at the track to get this leaf residue off Because it can cause major problems for the signaling system And just as also a quicker side one the other way of dealing with this is using axle counters instead So these are little things that are mounted to the track and they count the number of axles that go past Their sensor and they count it in at the beginning of a section and out at the end of a section And if one you counted it up you count up for in you count down again for out And if the answer is zero then there's no axles left in the section and that section is clear If you want to talk to me later, you can think about why The Swiss railway system has a regulation that no train may run with exactly 256 axles. I Am not joking you can run a train with 257 but not 256 and so anyway, I'm moving on them and The railways as we got into the 1900s started to introduce color light signals And there were two reasons for that one was that you can show more than just stop and go on a color light signal And the other thing is that you can control them from a long way away because it's just electricity You're not having to physically pull the levers for the mechanical lever thing Sometimes you really have to put your back into pulling it if it's a signal That's a mile away where it's a signal that's 20 miles away can be controlled easily as a color light And and they introduce something called multi aspect signaling where a signal could show one of maybe four different Aspects for different different views One would be stop which is a red light Another would be preliminary caution. So this is warning you that the next signal is going to be Caution and caution is warning you that the next signal is going to be red So you get double the amount of warning so as trains got faster They took even longer to stop and you needed more warning and you've also got a force clear So what would happen here is you've got a train in the distance there Just behind the train would be a red signal So you don't go into the back of the train before that would be a single yellow Before that would be a double yellow and before that would be a green And because they were using electricity now to control the signal So they didn't need these big levers to actually get mechanical effort. They could use tiny little levers So these were used in the in the early 1900s Livable lime food actually had them until a few years ago and they were used on the London Underground a lot until a few years ago But more widespread than this was something called nx panels which stands for entrance exit panels and These are designed in such a way That you don't have to press a lever or button for every individual signal or every individual point You have a long panel like this that shows a diagram of the railways on it So the all these black lines are tracks and you've got these little buttons And buttons and twisty knobs here and what you'll do is you'll say you want a train to go from here To here so you press the button at the beginning at the entrance the button at the exit at the exit And it sets up all of the points and all of the signals along the route for you So sometimes before you might have had to pull 20 levers for a single train to do a single movement Now you just press start stop and it does everything for you The way it does this is with a load of relays. It's got entirely electromechanical Interlocking so the relays set what you can and can't do so again It won't let you do something stupid like set conflicting routes or set routes into a section that's occupied with a track circuit And they also use the interlock the relays to do this entrance exit route setting part of it And you have a massive relay room underneath the signaling panel With maybe tens of thousands of relays in it and when you're in there when it's operating as I have been You hear all the relays clicking all the time So when a signal and sets a route it will go click click click click click click click I'm gonna train it enters the second or go click click click as they change the track circuits and so on. Some of you may remember this next accident, particularly if you lived in the south of England at the time. This was 1988 at Clapham Junction Station, which killed 35 people but injured almost 500. And this was an interesting one, because you had the line going from Southampton to London, and a train came along from Southampton towards London. And did you see what happened there? The signal was green, and as the train came along, it suddenly went red directly in front of it. Now that shouldn't happen. You should get a warning of yellow first. So the train driver stopped at the next signal, even though it was green, and phoned the signalman to go, you know, what's going on? This signal just went back to red in front of me. Unfortunately, while he was doing that, the signal behind him went from red to yellow, and another train came along from behind and crashed into it. And then, of course, as I said before, what happens next? A train comes on the other track and crashes into the wreckage. Now this was all stuff that should not happen, but signalling upgrades were taking place in the area, and there was what's called a false feed in the relay room. Basically, one of the relays was powered by a stray wire which touched the terminal. Now, all the wires should have been tied up out of the way when they weren't being used. They should have had insulation tape put on the bare ends of the wires, but they weren't. The signalling technician had been massively overworked with this re-signalling project, and there hadn't been good enough checking or wire counting, and that meant that this wire could be connected to the relay, giving it power all the time, and giving this what's called wrong side failure. After that, there was a lot of things changed to do with working hour limits, mandatory testing, different interlocking methods and so on. Also, radio communications with trains was a big thing so that you can send an emergency stop message to a train. But actually, there was a similar accident at Waterloo in 2017. Very similar causes, I mean, but very dissimilar outcomes. This didn't injure anybody or kill anybody. The train was going very slowly, and it went into the side of an engineering train. But it was caused by unauthorized wiring modifications in the relay room, and there hadn't been proper checking and wire counting again. So maybe we haven't learned the lessons from that. So just moving on to a few other things. One other problem you can have is driver ever. A driver can see a red signal but not notice it or forget it or not be paying attention or whatever, and pass the signal at danger, and we call that a SPAD, a signal passed at danger. And one of the worst SPADs was the Harrow and Wildstone crash in 1952, which was the second worst accident in the UK. And here you had a train sitting in Harrow and Wildstone station in North London, and you had a yellow distance signal, and two semaphore signals both at stop, and a train came sailing right past all three of those and crashed into it. And yes, yet again, a train came on the other direction and crashed into it as well. No one knows why this happened because the driver and fireman were both killed in the collision. It was a bit foggy, but not massively foggy, and all the other drivers had seen those signals. So whether the driver got confused or not seen them or forgotten about them, who knows? But he passed the signals at danger and went straight back into the other train. So to deal with this, they introduced something called automatic warning system. Now this is a set of permanent magnets and electric magnets that are located between the track, and the electromagnetic is energised or not depending on the state of the signal. And this is picked up by a magnetic receiver on the train, which means that if you go past a signal at anything other than green, so if it's at any of the cautions or danger aspects, then you'll get a little buzzer in your cab. The little display will turn out to look like that. It's called the sunflower display, that sort of sort of black and yellow pattern. And if you don't press a button in the cab to molly that within about two seconds of the bell going off, then the brakes will automatically be applied. Unfortunately, this doesn't still didn't work all the time. There was an accident at Labrack Grove, which none of you probably will remember. It was one of the spate of three or four big accidents that happened in the late 90s, early 2000s, near Paddington. And here you had a train that was coming out of London and a train going into London. And there was a red signal to wait while train two got out of the way before train one went across that crossover to where train two is, but train one went straight past the signal and crashed into it at quite high speed. Now, AWS was in operation here, but because AWS comes up every time you go past anything other than green, it comes up for like 50, 60, 70% of the signals you go past. Because if you're running on a congested railway near London, you're never going to have green signals because this train's too close to you. You're just going to have yellow ones. So the drivers get used to just cancelling it. It was a signal that was frequently spattered. It couldn't be seen very well. The driver had poor training. There was nothing called something called flank protection. They didn't have what should have meant that the points were changed to stop any kind of accidents like that, even if the driver had gone past the signal. And so since then, they've introduced train protection and warning system, TPWS, which does the same kind of thing as AWS, but a bit more cleverly. It has little transmitter grids between the tracks. And it deals with overspeed as well. So if a train is coming up to a signal too fast to stop at the signal, then the idea is this will notice in advance of the signal, apply the emergency brake, and the train will still stop at the signal. Whereas, of course, if your AWS goes off at the signal and you then start slowing down because the emergency brake comes on, you're going to be way past the signal by the time you stop. And this was introduced. It was installed in all high-risk locations by 2004. It's still only at some signals. It's not at every single signal, but it does the right kind of thing. And it definitely has helped reduce spats. So just to finish off really in talking about what the most modern form of signalling is, the most modern is what are known as integrated electronic control centres and the more modern version of rail operating centres, which are basically the same as the big panels, but they're all on computer screens. And the signaler uses a mouse or in fact a track ball to click signals on the screen. And again, set routes in this entrance exit way. So clicking a signal here, clicking a signal there, and it sets the route between them. Also, some of these systems have what's called automatic route setting. So in that case, he doesn't have to set the route for each individual train, but the computer system does that for him, assuming things are running to the timetable. Of course, when things aren't running to the timetable, which is quite often, the signaler has to do a lot more manual intervention. But the final example of where we can move to with this is in cab signalling. So this is moving from signals outside on the track to signals that are actually displayed inside the cab. And this is the cab of a train here. You can see that little display in the middle. It's got a fairly prominent speedometer on the screen. That shows you exactly what speed you should be doing to then be able to stop at the next signal. It shows you where you have movement authorities, as they're called, and how far you can go all electronically on that. And those are all done by these belazes, which are between the track, which are sort of passive radio transmitters that communicate where the train is, combined with mobile phone-based data, something called GSMR, which is basically the same as GSMR that you use for your mobile phone, but a railway version that's got good coverage of nearly all the UK railway network now to send information to the train. The benefit of this is you can move from fixed block signalling to moving block signalling. So earlier, you'd have these block sections that were between different signals or between different signal boxes. And they were static in size. You couldn't change them at all. With moving block, you can adjust the distance between trains based on how fast they're going. If your train's going at 120 miles an hour, it needs a longer stopping distance, so it needs to be further back from the previous train. If it's crawling along at 10 miles an hour to get into your terminus station in London, then it can be far closer to the previous train because it can stop. So you can move from the sort of high-speed indication at the bottom there to a lower-speed moving block. And then the final frontier, really, is automatic train operation. This has actually been running in the UK for quite a long time. The Victoria Line, when it was first introduced in 1968 in London, was automatic train operation. There's a button on the cab display, which says ATO Start. And the driver presses that and it drives itself automatically to the next station. The driver is still there to open and close the doors, monitor the systems and so on, but he doesn't actually do any driving in normal situation. The Docklands Lights Railway, you may also know, is driverless. You can sit at the front and enjoy playing with the pretending to be a driver, as I used to do when I was a child and still an adult, I think. And this had moving block. And this was since the early 90s. This had a moving block system to get better throughput on this kind of metro railway. So modern signalling in the UK is a real mixture. On one journey, you can come, say, from London to here, as a number of you may have done. You may have travelled on the Victoria Line, or even nowadays Crossrail in London, which has automatic train operation. You then come up through some modern rail operation centres that cover, there's one called Tennis Valley Signalling Centre, which covers London Paddington up to Diggcourt and Oxford on computer-based signalling. You'll then come up through some panel signal boxes around Oxford. You'll then come into a mechanically signalled area at Worcester and Malvern and Leadbury. So you've had all of this on one modern train doing a modern train journey in the UK, which I think is quite amazing, really, just the breadth of signalling practice that is around in the UK. So that's really all I've got to say here, so thank you very much. And feel free to come and talk to me afterwards.