This post is by Guy Shrubsole. Updated 16th Dec 2017 with post-script on Birmingham’s secret tunnels. 

The existence of a secret network of Cold War-era tunnels beneath central London can be confirmed by recently-released Land Registry data, Who Owns England can reveal.

There’s growing public interest in opening up previously hidden parts of subterranean London – from the unearthing of buried rivers, to the success of underground tourist ventures like the Cabinet War Rooms and the Mail Rail. But the authorities have remained reluctant to publicly confirm the existence of some of London’s most secretive tunnel systems – until now.

Last month, the Land Registry released free of charge its Corporate & Commercial dataset, which lists the 3.5 million land and property titles owned by all UK companies and corporate bodies. Some careful sifting of this vast dataset has uncovered various tunnels and underground chambers beneath London owned by the Post Office, BT, and the Ministry of Defence.

1. The Postmaster General’s secret tunnel beneath Whitehall

Browsing through the dataset, I stumbled across a very intriguing entry: a “Cable Chamber at the corner of Parliament Street and Bridge Street”, owned by ‘His Majesty’s Postmaster General’, who registered the freehold on 10th July 1951. Using the property title number, I decided to buy the title plan, to see precisely where this Chamber lies; it’s the small red square on the map below:

That puts it just outside the Parliament bookshop, near one of the exits to Westminster tube – here, on Google Street View:

Why this small cable chamber is interesting is because it appears to corroborate other stories about Post Office tunnels beneath Whitehall, long the subject of legend on urban exploration internet forums.

In 1980, Duncan Campbell, a journalist at the New Statesman investigating the government’s preparedness for nuclear war, found an entrance to some of the Post Office’s tunnels and rode a bike along them, somehow evading security. “A manhole cover, gently raised, gives access to one of the Post Office’s thousands of subsurface cable chambers”, he wrote, before following the tunnels down towards Westminster, “a Post Office lair called Q-Whitehall.”

Campbell published the resulting photos in the Christmas edition of the NS, in a brilliant piece that both mocked and excoriated the Cold War security state. This, after all, was the era of Protect and Survive and When The Wind Blows, when the government was pretending that households could survive nuclear attack simply by painting their windows white, whilst building themselves ever-deeper concrete bunkers. He went on to publish maps of the tunnel network in his book War Plan UK; the one of Q-Whitehall is reproduced below:

The Post Office tunnels were built in the 1940s, in the aftermath of World War II and with the prospect of atomic warfare looming. Aerial bombardment during the Blitz had forced the machinery of government underground, into the Cabinet War Rooms and elsewhere; now with the far greater threat of atomic strikes, it was decided that vital telecommunications channels should be buried deep beneath the surface so as to survive assault. One blogger has located an article about the construction of the Whitehall tunnels from a January 1946 Post Office engineers’ journal, published during the “short lived period where the government talked openly about what it had done during the war, before everything clamped down again as the Cold War started.”

Stephen Smith, a more recent chronicler of underground London, reckons that “no outsider has been into the tunnels since Campbell”. But at least with this new data from the Land Registry, we have official confirmation of their existence.

Campbell’s map of the Whitehall tunnel suggests that it has exit shafts under various government departments. So I decided to look through the Land Registry Corporate & Commercial dataset for any evidence of these. Sure enough, registered to ‘the Secretary of State for Defence’ (aka the MOD) is one “Vertical Shaft At Basement Level, Old War Office, Whitehall, London (SW1A 2EU)” – just as Campbell’s map shows. This raises fresh questions, however; since the Old War Office has been recently sold to the Hinduja Brothers, who are turning it into a hotel. Will access to the Whitehall tunnel remain closely guarded by the MOD, or will it become a tourist attraction for hotel guests?

2. The Atom Bomb-proof telephone exchange beneath High Holborn

Up until the 1980s, all telecoms was dealt with by the Post Office. Thatcher’s privatisation drive saw the hiving off of these functions and the creation of British Telecommunications Ltd (aka BT). Searching the Land Registry’s corporate dataset for BT’s land and property holdings throws up an even more intriguing set of secret underground tunnels, which it has inherited from its Cold War era predecessors.

In particular, this land title with a lengthy and mysterious description caught my eye: “That part of the subsoil which forms part of the underground works which became vested in Her Majesty’s Postmaster-General by virtue of the Post Office Works Act 1959 known as the London Works”. Interest duly piqued, I bought the title plan, and what it showed astonished me; a vast set of tunnels, shown in pink, stretching beneath High Holborn and Chancery Lane, deep beneath the level even of the Tube:

Digging further, I googled ‘Post Office Works Act 1959’, and turned up the transcript of a 15-minute debate held in the House of Lords on 20th January 1959. Lord Chesham, introducing the Bill for the government, assures his fellow Peers: “I do not think I need keep your Lordships very long in moving the Second Reading of this Bill… its purpose is to vest in my right honourable friend the Postmaster General certain deep-level chambers which were constructed under the Emergency Powers… Shortly after the war small underground shelters which had been constructed mainly in the borough of Holborn for the Ministry of Home Security were taken over by the Post Office. They were extended and they were adapted… All these works are now complete, and consist of underground rooms with connecting passages more than fifty feet below the surface of the ground. They are used for essential Post Office purposes”. Scant further details of the tunnel complex are supplied, but Lord Chesham had “arranged, for your Lordships convenience, for a copy of the book of reference and of the plans to be in the Library.” 

In other words, the plans reproduced above were never made fully public at the time.

Authors Richard Trench and Ellis Hillman, in their book London Under London (1985),  provide some more details of what became known as the Kingsway Exchange. “The Post Office pressed on with building its empire underground. Excavations began in 1951 for a vast underground telephone exchange at Kingsway. The backbone of the exchange was a twin tunnel 100 feet down on the northern side of High Holborn, between Hatton Garden and Red Lion Square, with Gray’s Inn Road running over it… Telecommunications plant, generators and repeating stations occupy most of the Hatton Garden side, while four extension tunnels, running beneath Chancery Lane Underground station, house switching units and an artesian well. A short cable tunnel links the exchange to the Post Office’s Holborn cable tunnel. The exchange, opened in October 1954, could handle two million calls a week”. (p.186)

After the end of the Cold War, Subterranea Britannica, a society of underground explorers, has been permitted to enter the Kingsway Exchange on two occasions. Their expeditions and photographs are online here. I took a walk around the area at ground level, and one sign of something odd going on below the surface is Number 39, Furnival Street, which looks to be one of the shafts where goods were sometimes transported in and out of the tunnels:

I’ve also discovered that the Kingsway Exchange appears in the Land Registry’s INSPIRE Index polygons for Camden, meaning that it’s easy to make a digital map of the tunnels (reproduced here for purposes of journalistic reporting):

The Land Registry records show that BT also owns a number of other tunnels and underground chambers:

• “Basement and Sub-Basement Cable Chambers, Cable Ducts, Tunnels and associated areas of Faraday Building North, Carter Lane, London”. A friend’s brother works for BT in their Faraday Building and has told me he’s seen evidence of these tunnels in the basement. Wikipedia notes that: “During the Second World War, the Faraday Building was transformed into a redoubt where the Cabinet could retreat if the need arose and the Prime Minister could run the war in greater security than Downing Street could provide.”
• “Cable chamber beneath Silver Street, London” and “the site of a cable chamber beneath part of the former site of Silver Street”. The title plan shows this to be near the Museum of London on London Wall.
• “Shafts and Tunnels at Moorgate Telephone Exchange, Fore Street, London (EC2Y 5BJ)” – again on London Wall, perhaps the same cable tunnel.

The Cold War is mercifully long over, and the paranoid secrecy of the state that accompanied it appears to have softened, at least in places. It’s a nice twist of history that some of the most secret Cold War sites are finally being revealed through the Land Registry’s embrace of more open data.

Post-script: Birmingham’s secret tunnels

After publishing this post, I was given a tip-off by @joolz_mc on Twitter that Birmingham, too, had similar secret tunnels under its city centre:

Similar to London I think. Evidence of ventilation shafts near the BT tower. I read when they were excavated workers were told they were for Birmingham’s underground. Can you access MapSearch on the Land Registry? I wonder if they are shown on there?

— joolz (@joolz_mc) December 16, 2017

So I took a look at the Land Registry’s INDEX Inspire polygons for central Birmingham, around the BT Tower (Brindley House and Telephone House) – and sure enough, there they were, a similar squiggly shape to the Holborn tunnels, buried beneath other more regular surface land parcels. (If you’re using QGIS to look for more tunnels like these, set the layer style to 50% transparency to reveal such ‘hidden’ polygons). Here’s a quick Google Map:

(It looks like one of the tunnels exits into a pub, The Queens Arms – might be worth asking the landlord if they have any really deep cellars…?!)

I bought the title plan for the Birmingham tunnel system [PDF], ownership of which was transferred to the Postmaster General in 1959, just like the Holborn network. Here’s a screengrab of the plan (North is on the right hand side):

If you know of any other secret tunnels, whether beneath London, Birmingham or elsewhere, please post details in the comments thread below!