Walking the Mail Rail Tunnels | Explore Under London!

Fancy exploring 70ft under London? You can now walk through the Mail Rail Tunnels, strolling deep below Farringdon…

Walking the Mail Rail Tunnels | Look Up London

But first things first, what’s the Mail Rail?

The Mail Rail was the result of congested London roads. In 1909 The General Post Office set up a committee to establish a more speedy and efficient system to deliver post across the capital and took inspiration from Chicago’s underground railway.

The plans were drawn up and by 1913 an Act of Parliament was passed. Work started in 1914 but – due to disruption from the First World War, the Mail Rail would only start running in 1927.

The London Post Office Railway Map, wikimedia creative commons c.1929

Covering 6 miles under London, it was the first fully automated driverless railway in the world and at its peak it carried 4 million letters every day, for 22 hours per day.

In 2003 the Mail Rail became too expensive to run and was moth-balled. It’s only since the Postal Museum opened in 2017 that members of the public can experience the Mail Rail, whizzing along the tracks in the tiny carriages.

Walking the Mail Rail Tunnels | Look Up London

But now there’s a new way to get see these subterranean passages, you can walk the Mail Rail Tunnels on foot!

Inside the Mail Rail Tunnels

The tour explores just under a mile of the tunnel system and whereas the Mail Rail stops at stations and shows projections and video explanations, it’s great to be able to experience the tunnels up close.

Walking the Mail Rail Tunnels | Look Up London

Here are some of the fun things we saw during our tour…

Safety Precautions

At various points along the route, the cast iron lining is reinforced with concrete. You can see the thicker section of wall below;

Walking the Mail Rail Tunnels | Look Up London

This is to ensure the River Fleet – one of London’s subterranean rivers – doesn’t flow uninvited into the tunnels.

Unfortunately, on occasion, it’s done just that. During construction, flooding caused a 1 month delay. Another fatal disaster struck with an explosion during the Second World War, with two men drowning.

This prompted a hefty-looking flood gate to be installed, however we were told on the tour that it’s never actually been tested (for fears it would never be opened again!)

Walking the Mail Rail Tunnels | Look Up London


We walked past the ‘Train Graveyard’. The only point of access for getting trains out is the depot (where we started our tour) so it’s very hard to remove anything from the Mail Rail tunnels.

Walking the Mail Rail Tunnels | Look Up London

These trains are all out of service but were once part of the 1980s replacement fleet.

Today there’s a better storage system in the form of a new maintenance section of tunnels to service the trains used by the public to ride the Mail Rail.

Walking the Mail Rail Tunnels | Look Up London


During the Second World War the Mail Rail tunnels, like many underground location across London, became useful as a storage area for the capital’s treasure.

For a few years the Mail Rail was charged with keeping none other than the British Museum’s Rosetta Stone safe from aerial attacks!

But there’s other artworks that can still be spotted underground. One is a curious chalk sketch of a horse;

Walking the Mail Rail Tunnels | Look Up London

Apparently no one knows much about it but the guess is it was either an urban explorer or distracted maintenance worker!

The other decoration down here is less of a mystery. In the early 1990s the Mail Rail had a sudden windfall of cash after its tunnels were used in a pretty terrible-looking film called Hudson Hawk.

The money was used to fund an annual Christmas party for the employees’ kids and other local school children. As part of the festivities the children would ride the trains and for one year a particularly artistic employee decorated the ’12 Days of Christmas’ on the walks in UV Paint!

Walking the Mail Rail Tunnels | Look Up London

They certainly brighten up the otherwise gloomy – but fascinating! – Mail Rail tunnels.

Walking the Mail Rail Tunnels | Look Up London

Mail Rail Tunnel Walks

If you’d like to walk the Mail Rail tunnels for yourself you can find out more on the Postal Museum website here.

Related Post Sculpture (11)
Get the latest London secrets to your email
See the city from a new angle, discovering little things you miss everyday and get the latest news about upcoming tours.
Once a week. No spam, just inspiration.
Your details will never be shared with any 3rd parties

More London Inspiration


  • Thanks for this interesting post and alerting me to the fact that walking tours of the tunnel are now possible. I did the Mail Rail tour a couple of years ago on one of those little trains; it was fascinating, although a little claustrophobic! Walking through the tunnels looks far more my thing, so I might give it a go next time I make a trip to London.

    December 1, 2021 at 10:31 am
  • Judith Barnett


    Walk? Wow! I have ridden though :-)

    December 1, 2021 at 12:07 pm

Post a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.