9 surprising facts about the Tower of London Moat

The Tower of London Moat wasn’t always the dry ditch that it is today. Did you know it was once filled with fish? Or that it has been used as an allotment?

The moat has experienced many changes over its nearly 1000 year history. Here are some surprising facts about the moat at the Tower of London. 

1. The first moat, built by William the Conqueror, was more of a defensive ditch

William the Conqueror’s great stone keep, later known as the White Tower, was once defended by a deep ditch on its north and west sides only.

The eastern side was defended by the ancient Roman London city wall, whilst the River Thames protected the south side. This early ditch was flooded by the tidal river water.

It wasn’t until the 1240s, under King Henry III, that work began on digging a moat that completely surrounded the Tower.  

2. The moat we see today is the same basic shape as it was in 1270 when Edward I expanded it

Edward I’s magnificent moat was created to keep attackers at a distance, and to prevent the undermining of a new curtain wall.

Edward refortified the wall by digging a deep, water-filled moat in the 1270s. This was so long-lasting and effective, that its basic shape survives to this day.  

It was at least 50 metres wide, and very deep at high tide. The ebb and flow from the river was controlled by sluice gates.

3. The moat was once full of fish

The moat also functioned as a fishery. In 1292, Edward I sent a large stock of young pike to be farmed there. The convenience of the moat as a food source continued throughout the centuries.

A perfectly preserved wicker fish trap, dating from the 15th or 16th century, was excavated from the moat, complete with fish skeletons inside.

4. By the 1840s the moat smelt so bad the Duke of Wellington was forced to drain it

Between 1843 and 1845, an outbreak of a deadly infection caused by poor water supply at the Tower was linked to the ‘obnoxious smell’ and ‘putrid animal and excrementitious matter’ of the muddy moat when the tide was out.

The Duke took the momentous step of having the moat drained and turned into a defensive dry ditch, or ‘fosse’.

The Tower’s moat has been dry (except for accidental flooding) ever since. 

5. The moat has been used as an allotment on more than one occasion

The dry moat became very useful to the Tower authorities and to the residents. The sunny south moat was used for growing vegetables from as early as the 1890s. Livestock grazed in the rest of the moat, keeping the grass nicely trimmed. 

During the Second World War, (1939-1945) the government introduced the 'Dig for Victory' campaign calling for the public to turn green spaces into allotments.

Everyone was expected to 'do his or her bit' to help the war effort as the government began to ration food.

The Tower of London was no exception, and the Tower's moat became an allotment providing Tower residents with produce during the war.

6. Soldiers camped in the moat for Queen Victoria's Diamond Jubilee celebrations

Queen Victoria celebrated her Diamond Jubilee in 1897 with huge military parades. Hundreds of the soldiers were encamped in the moat.

7. The moat became flooded with water again in 1928 after the Thames burst its banks

On 7th January 1928, the Tower moat flooded catastrophically after a downpour caused the Thames to breach its banks. For the first time, photography was able to capture how the moat looked when filled with water. 

8. The moat was filled with flowers for the Queen’s Silver Jubilee in 1977

Queen Elizabeth II's Silver Jubilee was celebrated at the Tower of London with a 260ft display of 470,000 begonia blooms in the west Tower Moat. The plants were given by Belgium, and 55 Belgian gardening experts travelled to the Tower to carry out the planting. The ‘carpet’ depicts the Royal and Belgian Coat of Arms flanking the Royal Cipher of Elizabeth II. 

9. In 2022, 20 million seeds were planted in the moat for the Platinum Jubilee

Over 20 million seeds from 29 flower species were planted in the Tower of London moat for Superbloom. This created a colourful, dramatic and vibrant field of flowers to celebrate the Platinum Jubilee of Her Majesty the Queen. 

Each of the flower species was specially selected for their colour and ability to attract pollinating insects, creating a new biodiverse habitat in the heart of London.