The existence of a secret network of Cold War-era tunnels beneath central London can be confirmed by recently-released Land Registry data

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.


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, [the author] 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, [the author] 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.