Tower Subway | History of this Odd Brick Structure by the Tower of London

Right by the entrance to the Tower of London, few people give a second thought to a little, round, brick building with Tower Subway written around the top.

Tower Subway - Northern Entrance - Look Up London

The structure only dates from the 1920s, but the writing informs you that Tower Subway was constructed in 1868.

But it still presents an intriguing question…

What was the Tower Subway?

Before Tower Bridge was finished in 1894, London Bridge was the only river crossing in this part of the city and was heavily congested.

A plan was hatched to dig an underground tunnel for trams between Tower Hill and (the brilliantly-named) Pickle Herring Stairs, just off Tooley Street.

Tower Subway Map

Image from Reynolds’ Shilling Map, 1895. Wikimedia Commons, Public Domain

It wasn’t the first tunnel to be constructed under the Thames (that honour goes to Brunel’s Thames Tunnel between Wapping and Rotherhithe from 1825-1843). However, the excavation was an important step in engineering.

It was first time that Sir James Greathead’s tunnelling shield was used.

James Greathead - Look Up London

Statue of James Henry Greathead in Bank Junction. Erected in 1994 and designed by James Butler. Look closely at the base and you can see it’s actually a cleverly disguised air vent for Bank Station below!

A tunnelling shield was the principle of forming a protective structure while digging through soft earth. It was first implemented by Marc Brunel, but it was Greathead – under engineer Peter Barlow – who improved the technique by using a circular shape.

In fact, it’s James Greathead who we can thank for the underground’s nickname; The ‘Tube’.

Related Greenwich Foot


Tower Subway opened for passengers in 1870, only taking a year to complete, however speed didn’t guarantee success.

The Tower Subway was similar to underground tube lines today, although with cables pulling carriages along rather than electricity. Each carriage could hold 12 people.

Image from Wikimedia Commons, Public Domain c.1870

Originally there were lifts that brought passengers back up to ground level and on the face of it, it seems brilliant, the whole process taking under 2 minutes to get across the river.

However, the lifts were plagued by breakdowns and there was one horrific accident where a poor man named Thomas had his head crushed in the lift shaft.

Tower Subway - Northern Entrance - Look Up London

Less than a year after it opened it had become a fully pedestrianised tunnel, with people paying a small toll to walk under the Thames. At its peak, one million people per year walked through it, pretty amazing numbers considering an average of 1.2 million use Greenwich Foot Tunnel annually today.

But with the arrival of the (free) Tower Bridge, that all changed. It closed in 1897 and was bought by the London Hydraulic Power Company as a convenient place for its mains under the Thames. Today it still houses water mains and telecommunications cables.

What Can you See today?

As you may have guessed by its size, this wasn’t the original public entrance to Tower Subway, but rather this is a 1920s replacement which gives maintenance access to the shaft below. But there is more. After all, a tunnel needs to have a Southern Entrance right?

The warehouses along Tooley Street have now pretty much all gone, swallowed by the More London development. But tucked out of sight you can find the site of the Southern Entrance;

Tower Subway - Southern Entrance - Look Up London

Far more mundane and modern-looking, it can easily be missed. But, even if it’s not as eye-catching, it’s still a sneaky clue to London’s history!

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  • Valerie


    Wow interesting read, thank you …

    November 18, 2020 at 8:36 am
  • Judith Barnett


    Gotta love a secret tunnel (& “The Tube factoid” – brilliant) in London 🙂

    November 18, 2020 at 9:38 am
  • Anne Fauconnier-Bank


    Had noticed the round tower, so enjoyed reading about it, thank you Katie.

    November 18, 2020 at 10:44 am
  • David Paskell


    That’s another fascinating fact about London I’ve just learnt from you Katie. Thank you very much

    November 18, 2020 at 1:23 pm
  • Maureen Richardson


    I was so thrilled to walk under the Tihames on the Greenwich Tunnel for the first time & have done it again.

    November 18, 2020 at 4:00 pm
  • Adrian Butters


    Thank you Katie for this interesting piece. I had heard of the Wapping Rotherhithe tunnel, and this has been featured on tv programmes recently, but I wasn’t familiar with tower subway, very much a curiosity nowadays (enjoying its life as a service tunnel nowadays). Keep up the good interesting work, thank you.

    November 18, 2020 at 11:07 pm
  • Great Post, Katie! Thoroughly enjoyed it and next time I head to towards the Tower of London I shall be keeping my eyes peeled for the old structure, plus not to mention that Tooley St is now on my list because I want to see the location of the old southern entrance too! Thanks for the really interesting insight 👍

    February 9, 2021 at 5:27 am

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