I have a weird conspiracy theory about this bridge

[00:00:00]I said I was going to film something interesting in every English county on this road trip.

[00:00:04]Shropshire is a beautiful county, full of history and gorgeous scenery, but in terms of things that work for this channel and this series... it’s very peaceful, and it turns out... (whispers) there’s not much there!

[00:00:16]But I said every English county, so welcome to my slightly unhinged conspiracy theory about the Iron Bridge.

[00:00:24](birds twittering) As unhinged conspiracy theories go, I think it’s a fairly benign one.

[00:00:31]And I think it’s one that no one else shares.

[00:00:33]I think I came up with this one myself.

[00:00:35]Which is why I’m in the town of Ironbridge to look at this iron bridge with this angle finder thingy.

[00:00:45]World Heritage Site, famous around the world, and also, still a working bridge, closed to vehicles these days, but a useful way of getting across the River Severn for people who live in the town.

[00:00:54]Let me introduce you to Matt from English Heritage, who couldn’t be there on the day, but who I later interviewed on a video call while I was sitting in a service station car park.

[00:01:03]The Iron Bridge is one of the most significant monuments that we’ve got within the National Heritage Collection.

[00:01:09]But it’s right there in the town.

[00:01:11]People walk over it to go to school every day, and to go to and from work, or as tourists to visit it and look at the fantastic view.

[00:01:17]So, it’s a really interesting thing to think about curating and managing and conserving because it exists not in a glass box, but in a real community, surrounded by real people.

[00:01:29]The most important thing to bear in mind is that this is the first iron bridge.

[00:01:34]The first major cast-iron bridge ever built.

[00:01:38]There’s some evidence for a small one in a garden in Yorkshire that was built a few years earlier, and admittedly, China had suspension bridges with iron chains a thousand years before, but this was a first.

[00:01:47]Molten iron, cast into massive pieces, spanning a long distance high over a dangerous river.

[00:01:52]There’s a direct path from that bridge to the Eiffel Tower, to every steel-framed skyscraper ever built.

[00:01:57]Completed in 1779, opened 1781.

[00:02:04]That’s why it’s important, but that’s also the first part of my conspiracy theory.

[00:02:08]This was new technology.

[00:02:10]So, why build it out of almost-experimental metal when stone works just fine?

[00:02:16]Iron had been produced in that very area for centuries before the Iron Bridge was constructed, a very long tradition of iron founders.

[00:02:27]The bridge itself was a necessity.

[00:02:28]And there’s many instances of people drowning trying to get across it in ferries.

[00:02:32]But I always like to think that building it out of iron was kind of like a calling card.

[00:02:36]The ironmasters. “Look what I can do.”

[00:02:38]“Look what we can do in this area “with this material that we produce in such fantastic quantities.”

[00:02:45]Nothing like this had ever been attempted before, not on this scale.

[00:02:48]And building it out of iron might well have just been showing off.

[00:02:52]But there are no surviving plans.

[00:02:55]I don’t seem to be able to find any plans or designs or blueprints for it.

[00:03:00]Has anything survived there?

[00:03:02]I couldn’t find anything but one sketch of it being under construction.

[00:03:08]Ah, right, so that’s the Elias watercolour of it being under construction.

[00:03:12]That was found relatively recently, 20, 25 years ago maybe, and that’s the only image we have of the Iron Bridge under construction.

[00:03:21]And indeed, provides us with fantastic evidence as to how they went about building the bridge.

[00:03:26]That painting was only discovered in a museum in Stockholm in 1997.

[00:03:29]It helps with a bit of historical knowledge, but doesn’t affect the conspiracy theory.

[00:03:33]Now, the architect, Thomas Farnolls Pritchard.

[00:03:37]There are some surviving drawings by him from the years before construction, but those are just ideas, not actual designs, well, they didn’t have blueprints back then, but you know what I mean.

[00:03:48]Those are nowhere close to what was actually built, the designs are very different, and they all have this smooth arch to them, not the pointed peak of the Iron Bridge.

[00:03:57]And Pritchard died one month after work began, his final design was approved, but again, no records of what it actually looked like.

[00:04:04]The original drawings show a much flatter bridge as opposed to with that quite distinctive angle on it there.

[00:04:13]That’s all the historical evidence for how the bridge was meant to look.

[00:04:17]And so, my conspiracy theory: I think that bridge was meant to be flat, or at least, much closer to flat than it actually is.

[00:04:23]And maybe there was meant to be a little bit of an angle, but... if you visit there, one of the things you find is that it’s really steep.

[00:04:30]As a comparison, the modern guidance for wheelchair ramps is that they’re no steeper than a 1 in 20 gradient, one metre of rise for every twenty metres of ramp.

[00:04:38]They can be a bit steeper if they’re short, and, obviously, there weren’t those standards back then, but the Iron Bridge is one in eight, it’s really noticeably steep.

[00:04:46]Why would you build a bridge like that?

[00:04:48]Okay. Next bit of evidence.

[00:04:50]This painting by William Williams, from 1780.

[00:04:54]Several weird things about this painting.

[00:04:56]First, there are multiple slightly different versions of it.

[00:04:59]It turned up at auction a few years ago, and the auction description refers to the other version, the one in the Ironbridge Museum’s collection, as the “prime version”.

[00:05:08]Second weird thing.

[00:05:09]This was painted after the bridge’s construction but before it was actually opened to the public.

[00:05:15]But that bridge looks open to me.

[00:05:17]What you’re looking at is a piece of publicity.

[00:05:18]You can’t take the bridge to London for all of the... You can’t pick the bridge up, take it to London where the Royal Society or the people that you want to impress are.

[00:05:28]What are you going to do?

[00:05:29]Well, you’re going to commission an artist to do this fantastic painting and the painting can travel.

[00:05:33]It’s as much a piece of industrial advertising as it is kind of reportage, you know, like a documentary.

[00:05:39]I feel that’s a piece of promotional work.

[00:05:43]So, the famous painting of the bridge.

[00:05:46]Doesn’t that painting look less steep than the real bridge?

[00:05:49]We can get a similar shot from the drone, and, yes, the angle will look different depending on where you put the camera, but from that far back it shouldn’t change much.

[00:05:55]The painting puts it at about a three-degree angle at the top.

[00:05:59]With the drone footage I took, it looks like it’s about a four-and-a- half-degree angle, but crucially, it’s uneven on one side.

[00:06:06]I only realised that when I was on the bridge.

[00:06:07]That... is not a straight line.

[00:06:10]That goes boom, boom, boom.

[00:06:12]Why would you build a bridge with an uneven approach?

[00:06:15]I’d turned up with my angle measurer to get a precise reading off the top, assuming that the approaches would be flat, but they weren’t.

[00:06:21]Also, the top didn’t have a sharp angle, it was a gentle curve, which meant I had more problems.

[00:06:26]Do I have to measure every single one of these joints?

[00:06:31]I think I have to measure every single one of these joints.

[00:06:34]Alright.

[00:06:36]183.0? Really?

[00:06:38]Okay, that’s going up.

[00:06:40]Suffice it to say, me and my little angle measurer did not get any useful data.

[00:06:46](sighs) Not entirely convinced about this strategy anymore.

[00:06:50]The bridge is kinda lumpy.

[00:06:53]But that’s partly going to be ironwork and partly going to be a lot of resurfacing over the years.

[00:06:56]So, angle measuring, bad idea.

[00:06:58]But there is one more piece of evidence to talk about, which is that the entire Ironbridge Gorge is very slowly collapsing.

[00:07:05]I like to refer to the gorge as a dynamic landscape, which is I think a great way of... That’s a very polite way of saying it’s... it’s a nightmare to build on.

[00:07:16]It’s moving, right?

[00:07:17]What you’re looking at is centuries of industrial activity with adit mines.

[00:07:23]So these are mines that rather than going sort of straight down to get to what it is you want to get to, you go in the side of the gorge.

[00:07:29]The water has come through over, you know, millions of years and actually erodes away and exposes layers of geology.

[00:07:36]So, you’ve got easy access, right?

[00:07:39]Why go a mile over that way and then have to dig down to get to what you want when you might have the opportunity to get to it a lot easier?

[00:07:48]For centuries, that gorge has been mined, and there are so many landslips.

[00:07:52]I didn’t know there was a National Landslip Database, but there is, thanks to the British Geological Survey, and there are so many landslips in that area.

[00:08:00]This book.

[00:08:02]This book here... I can’t pin the book, so... this book, which is pretty much the definitive history, it talks about multiple repairs to the bridge, suspicions that the sides of the gorge were closing in, and there were cracks appearing and things had to be shored up and replaced all the time.

[00:08:16]The construction was not great in hindsight, things kept breaking, because what happens if you put hundreds of tons of iron and stone on the side of a gorge that’s already prone to slips and riddled with mining?

[00:08:26]The land is going to subside, it’s going to crush down and push together.

[00:08:30]And this bridge is the first, the world hadn’t developed the technology yet.

[00:08:35]Okay, English Heritage describes them as using “carpentry techniques” to put iron together.

[00:08:40]In the 1970s, engineers built a concrete strut between the two sides of the bridge, under the river, to try and keep the sides in place.

[00:08:46]There are so, so many references to the land slipping.

[00:08:50]And I found an article from the Times in 2018, during the last restoration, that said, “Over 240 years, the gorge has narrowed, “compressing the span of the bridge by 306mm.”

[00:09:03]Which is clearly... rubbish.

[00:09:06]No-one has data that precise for the last decades, let alone centuries.

[00:09:09]And 306mm is one foot.

[00:09:12]Twelve inches, almost exactly.

[00:09:14]Which means the journalist maybe interviewed someone who said, “Eh, it’s probably slipped about a foot.”

[00:09:18]Wrote down, “It’s slipped by 12 inches.”

[00:09:21]And a sub-editor who doesn’t understand how to convert things properly changed that to metric as 306mm.

[00:09:27]Or, they could have said, “It’s slipped by about one percent,” because weirdly, the bridge span is 30.6 metres, exactly one hundred times that amount.

[00:09:36]Either way, that’s clearly wrong, but that’s at least a rough number.

[00:09:40]So, I made a visualisation tool.

[00:09:42]And if we assume that the bridge was meant to be flat, we plug in all the numbers, a 30-centimetre crush on a 30-metre flat bridge, that gives an angle of more than eight degrees at the peak.

[00:09:56]Which is far more than the bridge actually has.

[00:09:58]If we assume it was meant to have a gentle angle, about two degrees at the top, and it was only compressed ten centimetres over hundreds of years, that’s still a five degree angle, still more steep than it actually is.

[00:10:09]So that promotional painting, which is now hidden under here, it might be accurate, the bridge might still have been rising.

[00:10:16]I think whatever happened, happened quite quickly as the land settled under the new weight of iron and stone, and they were lucky that the early iron construction was able to deal with it.

[00:10:26]The sun is setting behind a cloud, the last of the tourists have left, and the shops have shut down.

[00:10:31]There’s no more footage, no more evidence that I can get.

[00:10:34]It’s not really evidence, though, is it?

[00:10:36]It’s just a conspiracy theory.

[00:10:38]And to be honest, those thrive on lack of evidence.

[00:10:40]In fact, I think the lack of evidence actually just helps my conspiracy theory.

[00:10:44]’Cos, you know, I’m probably slandering someone from two centuries ago here, but if I was a senior engineer on this bridge, if I got all the plans laid out and it was meant to be almost flat, and then they put the stone in and they put the iron in.

[00:10:56]And then over the next few years, the stone slowly sank and the bridge slowly rose, I might think... It’s a bit embarrassing, that.

[00:11:06]Want to get rid of those original plans that show it flat, ’cos, uh, you know... a couple of centuries’ time... I want people to think that it always looked like that.

[00:11:15]That’s how it was meant to be.

[00:11:17]And it probably was.

[00:11:19]But there’s still a bit of my head that’s like... that was meant to be flat.

[00:11:25]That was meant to look like the Iron Bridge, and we got this in one take, and I am not convinced that looks like the Iron Bridge at all.

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