What is the Pool of London?

For nearly 130 years, Tower Bridge has stood as the physical and symbolic gateway to London, spanning the historic heart in a stretch of the Thames that is known as the Pool of London.

The Pool starts at London Bridge and flows downstream beneath Tower Bridge, to where the river bends to the north between Rotherhithe and Wapping. It is divided into two parts, the Upper Pool and the Lower Pool. The Upper Pool runs from London Bridge and the Cherry Garden Pier, in Bermondsey. The Lower Pool consists of the section between Cherry Garden Pier to Limekiln Dock, Limehouse.

From Tower Bridge's high-level Walkways, you can see the entire Pool of London, 33.5 metres above road level. It's quite an unforgettable sight.

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How did the Thames get its name?

Just a few years after the Roman invasion in 43 AD, a small trading settlement was established on hills on the north side of the river. The name for that settlement? Londinium. 

The river’s name is even older, although its origin is not fully known. It is believed 'Thames', from Middle English Temese, is derived from the Celtic name for river, Tamesas, recorded in Latin as Tamesis. The syllable 'tam' indicates 'smooth' or 'wide-spreading', while 'esa' steam from a root meaning 'running water'. What is certain, however, is that the 'Thames' is one of the most ancient names recorded in England.

In any case, 2,000 years ago, the river was very different to the one you see today.

Image: Plan of London from 1833, showing the supposed topography of Roman London © London Metropolitan Archives

Aerial photo Tower Bridge and London Bridge

The Thames then and now

Over a thousand years ago, the Thames was wider, with large areas of marshland stretching off to the south. The incoming tide reached a series of small gravel islands, where Roman engineers spanned the river, creating the first London Bridge. 

London’s geographical position helped it grow. Taking advantage of the river’s natural flow, ships would enter the Thames estuary between Kent and Essex, and the incoming tide would bring them effortlessly up to the capital. To return to the English Channel, they waited for the next outgoing tide. A thriving port developed in the Pool of London.

In modern times, rivers and seas are often seen as barriers to be crossed. By contrast, until the invention of the railways in the 1800s, travel by water was a far more efficient way to move goods and people than trying to go by land.

Butler's Wharf by Otto Berkeley

Where is the port today?

The size of shipping has grown over the centuries, while the port has slowly moved further and further downstream to the east.

Back in the 1500s, ships usually weighed around 150 tonnes. By the early 1800s, vessels could weigh around 500 tonnes, reaching 7,000 tonnes in the 1900s - in 1909, the Pool came under the jurisdiction of the Port of London Authority, founded on 31 March of the same year.

Container ships weighing up to 200,000 tonnes now use the London Gateway, about 50 miles downstream. To put that in perspective, HMS Belfast, which you can see from Tower Bridge, weighs in at a 'mere' 10,000 tonnes.

With the Pool of London seeming quiet these days, it’s perhaps a little hard to imagine that when Tower Bridge was completed in 1894, this was the busiest port in the world, with goods such as cotton, sugar and tea coming and going to all parts of the globe.

75% of London’s fresh food, for instance, was unloaded at the warehouses in the Pool. These warehouses can be seen on the south side at Hay’s Galleria, Butler’s Wharf and the Shad Thames.

Image: Butler's Wharf photographed from Tower Bridge's high-level East Walkway © Otto Berkeley

Tower Bridge under construction

A busy city

By the 1880s, a new river crossing had become a desperate priority as the population of London boomed. While the port and the city flourished, there was no permanent river crossing between London Bridge and the sea.

The importance of the port and the volume of shipping was the main reason why Tower Bridge was designed to raise, to allow unhindered access to the upper reaches of the Pool.

Until the 1930s, the Bridge would lift around a whopping 9,000 times a year!

Even though the docks have moved far to the east, the Thames is still an important transport artery.

London remains one of the country’s busiest ports. And as for Tower Bridge, it continues to lift around 800-1,000 times a year, allowing ships in and out of the Upper Pool, between London Bridge and the Cherry Garden Pier.

Discover inside Tower Bridge and experience our high-level Walkways, around 42 metres above the Thames.

More to explore

There is so much more to discover inside Tower Bridge, from the unique views of London to the history of the landmark.