Welcome to Londonist: Time Machine.
Last week, I spent an hour crossing London Bridge. Not on the top, but inside. Very few people know about the chambers within the bridge, and a vanishingly small number have ever been inside. What follows are some very rare photographs from this secret space below the carriageway, including some fragments of the earlier London Bridge.
First, a quick message…
🍺📣 Thanks to everyone who came along to our drinks evening at the Cittie of Yorke (and thence Ye Olde Mitre) last week. I’ll be arranging another in a couple of months. These events — a chance to meet other London history fans in an historic environment — are only open to paying subscribers. I’m also finalising a time for our next site visit, a small, little-known museum, which I’ll talk more about soon. If you’d like access to such events, as well as bonus newsletters and the full Londonist: Time Machine archive, then just follow the button below. It’s less than the price of a pint a month, and it helps keep this ad-free newsletter going. Thanks!
Inside the Hidden Chambers of London Bridge
Millions of people walk across London Bridge each year. Only a handful get to crawl through it.
I’m down on my hands and knees, garbed in high-vis, boots and hard hat. I must squeeze through an aperture the size and shape of a toilet. Round my waist, emergency breathing apparatus plays conkers with my pendant camera. It’s not quite what I’d pictured when asked if I’d like to visit the inside of London Bridge.
To be fair, this was by far the tightest squeeze in what is a surprisingly spacious sequence of chambers. My expedition through the interior of London Bridge would take me clear across, from north to south. All the time, thousands of people scurried above, completely oblivious to the band of adventurers squeezing through the concrete beneath their feet…
Before we get stuck in, let’s just clear up some nomenclature, so you know which bridge(s) I’m talking about during the historical interludes. There have been many iterations of London Bridge. The Romans built one (or more) wooden spans, and at least two crossings were put up in early medieval times. Very little is known about these. For our purposes, you need only consider the following:
Old London Bridge (1209-1831): The one with all the houses on.
John Rennie’s Bridge (1831-1967): The one they sold to Arizona.
Modern London Bridge (1973-present): The one I am in.
Tower Bridge (1894-present): The one people think is London Bridge, but isn’t.
All of these bridges have one thing in common (besides spanning the Thames). Every one has been managed and maintained by the City Bridge Foundation (formerly the Bridge House Estates). Over 700 years old, this venerable institution looks after all the non-rail bridges in the City; that is, Blackfriars, Millennium, Southwark, London and Tower. They built the John Rennie bridge from scratch without using public money. They did the same for the modern London Bridge, stumping up £4 million (over £70 million in today’s money). Their ancient coffers also help fund community projects all over London, via £30 million of grants per year. This remarkable charity has a fascinating history in its own right, which I’ve written about here. It is they who have kindly granted me access to the hidden bits of London Bridge.
Our present bridge is not, it has to be admitted, the most comely of spans. In appearance, it is almost as simple as a bridge of this size can be. Its shallow arches are supported by just two river piers. This is a functional if not an aesthetic advance on the 19 piers needed for Old London Bridge, and even the four piers of Rennie’s bridge.
The bridge was designed in the 1960s by Lord Holford, whose draughtsman’s fingers are all over post-war London (he was one of the guiding lights behind the pedway scheme or raised walkways, which I covered recently). In engineering jargon, the bridge is formed from prestressed-concrete box girders, with structural steel support. The key word in all that is “box”. A box implies a hollow interior. And where you have a hollow interior, you can suit up and have an adventure…
Shrinking inside the box
The expedition begins on the north bank. I’m not permitted to reveal where. Let’s just say, it’s not what I expected.
The first chamber I can talk about extends across the width of the bridge. It is dark, dingy and replete with cables. I’m surprised to find, however, that this is not an entirely concrete structure. In the north-east corner, a small patch of brick and stone survives from John Rennie’s bridge. The concrete has been grafted on to his 200-year-old bridgehead.
From this room, eight long chambers extend out through the bridge. Each can be entered through a small, numbered window. It’s like one of those decision points in a fantasy role-playing game. Choose carefully: one way leads to treasure, the others may disturb orcs and goblins.
Happily, the accompanying engineers know exactly which route to take. Tunnel 8 is the least cluttered with cables and drainage. It is, in fact, empty apart from the wiring for the Illuminated River lights on the outside of the bridge. To enter Tunnel 8, I have to scramble through a square portal, over a drain, and on through another window. Years of training (i.e. hanging out with my kids in softplay) have prepared me for such manoeuvres, though I can’t say I’ve ever slogged through my local FunZone with several kilos of emergency oxygen strapped to my waist.
Through the hatch, we enter a string of much larger chambers. As you’d expect, these vary in height and camber as we progress along each arch. Occasional steps mark places where the bridge’s steel tension cables are anchored in place. It is possible to walk upright, almost as far as the apex of each arch.
We reach the north pier, and here I’m in for an unexpected treat. A side opening leads into the parallel tunnel, number 7. This contains the remnants of the bridge’s underfloor heating system. This ingenious set up was thermostat-controlled1, and would switch on at 1℃ (34℉) to melt ice, or 0.5℃ (33℉) to tackle snow. It stopped working long ago. Presumably, cheap old grit works just fine.
More surprises await through the next aperture. This leads into one of the deep grooves below the bridge, which you might have noticed if you’ve ever sailed underneath. I was able to stand on what must be one of London’s least visited balconies and watch boats passing below.
I return to tunnel 8 and continue south. The ceiling gets lower as we approach the mid-point, and we must stoop, then crawl over a grille. The gentle descent to the south bank then mirrors the first half. As we walk along, I’m struck by the silence. A steady stream of traffic, including trucks and double-deckers, are passing almost overhead. They are barely audible. Such are the muffling qualities of concrete. Perhaps even more surprising is the lack of smell. The interior is largely watertight, and difficult for birds and vermin to penetrate. There isn’t much here to provide an aroma, save for my increasingly sweaty back.
The transpontine landing is very different to its northern counterpart. Here, the Thames can be glimpsed through various openings. We also get a fresh insight into the bridge’s structure. Remarkably, the entire weight of the deck and all its cross-river traffic is carried on just eight supports per pier. Each has the diameter of a dinner plate.
This end of the bridge connects up with the largest remnant of the John Rennie bridge. You’ve probably seen it. The section of Tooley Street near Southwark Cathedral runs underneath the bridge approach, and the arch you pass through is a leftover from that otherwise-demolished bridge. Further sections survive closer to the river, but I could not see them from our finishing point. They’re locked away inside yet another secret chamber, used by a gun club for rifle practice. That sounds like an article for another day.
I left the crossing with a new-found appreciation. Yes, London Bridge is no beauty queen, but it does have a ‘functional grace’ of its own. Those long, shallow spans are soundly engineered, and really do soar when viewed from beneath. They are even more remarkable when seen from within.
Update: And here’s an excellent video of the expedition, by the City Bridge Foundation.
My thanks to the City Bridge Foundation for granting me access, and helping me through the structure. Sadly, public tours are not available.
Thanks for reading! As ever, I’d love to hear your thoughts in the comments, or email me any time on matt@londonist.com (particularly if you have access to somewhere unusual and historic!).
According to the Illustrated London News, 1 March 1973.
Just when you thought to have read everything about London there is to know, you've found a new 'discovery'. Amazing Matt.
Utterly fascinating! Extra points for sneaking in a reference to the Death Star trench run! :)