Deep under the streets of London the ground is riddled with a labyrinth of tunnels, cellars and chambers. Some like those of the London Underground network are used by thousands of people everyday on their commute to work and for visiting the capital’s shops and tourist attractions, but others possess a more secret history. Now one of those secret networks, the Mail Rail (formerly known as the Post Office Underground Railway) has just opened its doors to the public and is proving to be a big hit as visitors book up London’s newest bizarre tourist attraction.

The nearest London Underground station is Farringdon and from there it’s a short walk to Phoenix Place where at the rear of Royal Mail’s massive Mount Pleasant sorting office you will find the portal to Mail Rail lurking. It’s a new addition to the National Postal Museum just over the road and the price of your ticket will also give you admission to their main building. Leading, naturally via the obligatory shop, a set of stairs descends to the huge vaulted chamber that was the railway’s former engineering depot. Now converted to a museum gallery, this is the starting point of our subterranean journey, 70 feet below the streets of London. This 20 minute ride is not an experience for the claustrophobic. The train at the platform is tiny, with room only to squeeze two small people or one more comfortably upholstered individual like myself within each of the carriage’s narrow compartments. There is no driver at the front either, but then this railway was never really intended for people.

Originally running six and a half miles from Royal Mail’s Whitechapel sorting office in East London to Paddington Railway Station in the west, the Post Office Underground Railway was conceived as a means to take mail off Edwardian London’s congested streets. There are a total of 23 miles of tunnels including sidings and eight stations but our ride only takes us around the maintenance loop that encircles Mount Pleasant.

I clamber into the carriage and a Perspex canopy is slammed down over our heads, it’s almost like being sealed in the cockpit of a fighter jet. I attempt to sit up straight to take in the view and my head rests on the canopy. A lurch and the train lumbers forward, gathering speed as we take off into the tunnel. Overhead stalactites glint in the locomotive’s lights as former railway engineer Ray Middlesworth’s recorded commentary explains how our route will take us to Mount Pleasant’s westbound and eastbound platforms where we are shown some pretty impressive state of the art sound and light shows. One gives us a potted history of the line, while the other brings to life the hustle and bustle of a busy platform crew in action, so detailed that it even includes one of the networks legendary cats.

Much indulged by the station posties these moggies were just a few of the cats on the official Post Office payroll. Their job was to keep down the mice who found the old cloth mailbags just too tasty. In 1873 the cats were put on a weekly wage of one shilling and sixpence (seven and a half pence in today’s money). In 1952 this meagre allowance was increased to two shillings and sixpence (twelve and a half pence) after questions about the cat’s welfare were raised in Parliament. Some of these Post Office cats became the stuff of legend, one such kitty was Tibs the Great (1950 –1964) whose obituary was run in some of the nation’s newspapers. When he died Tibs tipped the scales at 23 pounds, which probably had more to do with his habit of hanging about the staff canteen than munching on mice and rats.    

It’s no surprise that Mail Rail’s tunnels look very much like those of the London Underground, they were bored through the London clay using a Greathead Shield System in the same way that deep cut lines such as the Northern Line were constructed. However, Mail Rail’s tunnels are a lot smaller, barely nine foot (two metres) wide across. Within the tunnels there are two narrow gauge (two foot or 60cm) tracks that separate on either side of the station platforms. As we roll on through the loop Ray’s commentary points out the heavy steel flood doors installed in case the subterranean River Fleet should burst through the tunnel’s cladding along with the ghostly pit of the locomotive graveyard where the cannibalised carcasses of broken rolling stock enjoy their final rest. In what seems hardly any time at all, we are delivered back into the depot platform and released from our carriages to enjoy the vintage rolling stock and other items on display in the museum’s collection.

So why did the Post Office build an underground railway? In the early 20th century nearly all communications went by post since there was no internet and very few telephones, but moving millions of items from one end to the other of the capital of the world’s largest empire through streets clogged with horse drawn vehicles and hand carts proved to be an absolute nightmare for the Post Office management.

The solution was quite logical. In 1863 the first of London’s underground railway lines had opened, moving people around the capital far more rapidly than before so why not do the same for letter and parcels. Visits were made to the Chicago Freight Subway System and a similar subway in Berlin before plans were drawn up for an all-electric network of driverless trains. In 1915 work began upon the tunnels linking seven sorting offices and two of London’s busiest railway stations. Construction was held back during World War One, when the tunnels were used to keep items from London’s museums and art galleries safe from German Gotha bombers, and the railway completed 1927.

From 1927 up to until it’s closure in 2003 the electric trains of the Post Office Railway (rebranded as Mailrail in 1987) sped mail under London’s streets for 23 hours a day, 286 days a year (no service on Sundays and bank holidays). The journey from Whitechapel to Paddington took 26 minutes allowing for stops along the way. At each station a dedicated group of subterranean postmen would load and unload the mailbags, moving up to four million items of post a day at the height of its operation.  However by 2003 a combination of dropping mail volumes and the transfer of mail processing to new mechanised mail centres in different locations rendered Mail Rail no longer economically viable.

London’s secret railway enjoyed a brief moment of fame when Bruce Willis concealed himself in one of the rail cars to break into the Vatican in Joel Silva’s adventure comedy Hudson Hawke (1991), needless to say there is no ‘Poste Vaticane’ underground railway in Rome. It is also featured in Lawrence Leonard’s novel The Horn of Mortal Danger.

Mail Rail is open everyday from 10am to 5pm. Admission including entry to the nearby National Postal Museum and your train ride, is £16 for adults. Mail Rail is at 15-20 Phoenix Place, London, WC1X 0DA nearest tube is Farringdon, nearest mainline rail station is Kings Cross/St Pancras, book tickets at