Things to See and Do

Fortress Falmouth and the First World War

Discover Falmouth’s role in the First World War in the Fortress Falmouth exhibition at Pendennis.

Fortress Falmouth Exhibition

The Fortress Falmouth exhibition at Pendennis Castle marks the centenary of the First World War and explores:

  • Personal accounts from the men and women who went to war
  • The War at Sea which took place in the channel, and all around the Cornish coast
  • The Spymania which arose from Falmouth’s war status as a defended port

Built by Henry VIII to defend the Fal estuary, Pendennis Castle has guarded the port of Falmouth for over 400 years. At the outbreak of the First World War, Falmouth was placed on a war footing as a Defended Port, and Pendennis became its military headquarters. Strongpoints, checkpoints and trenches defended the approaches to the town and thousands of troops came for training before going off to war. At its height at least 7,000 and perhaps as many as 14,000 troops were stationed within the area of Fortress Falmouth.

The exhibition explores Falmouth's time as a Defended Port, bringing to life the challenges of living in a coastal fortress, with photographs, artefacts and first-hand accounts of soldiers stationed in the town.

Two storey stone barracks at Pendennis Castle
The Royal Artillery barracks at Pendennis Castle

Personal Accounts

The exhibition features letters from men and women who served their country during the First World War, including some from one of the soldiers stationed at Pendennis for artillery training. Battery Sergeant Major John Glasson Thomas, who wrote to Miss Getrude Brooks between 1915 and 1917.

John - nicknamed 'Tommy' - joined the Royal Garrison Artillery in May 1915 and was posted to Pendennis for training on heavy guns. His letters give a strong sense of his personality – his sense of humour, likeability and intelligence. He recalls high-spirited nights in the barrack rooms; the threat of attack from the sea; and the thrill of finally being drafted to France in October 1916.

He survived the battle of the Somme, but was killed on 11 August 1917 during the third battle of Ypres. Gertie treasured the letters and memories until her death in 1960. Several of the letters are on display in the new exhibition, on loan from the St Ives Archive Study Centre.

Read more of John’s story in his own words in the exhibition at Pendennis.

John Glasson Thomas (Tommy)
John Glasson Thomas (Tommy)

War at sea

Falmouth's location at the south-west tip of England gave it an important role in the war at sea. In 1914 the Royal Navy was the largest naval force in the world, and the Germans avoided open sea battles. Instead they targeted vessels with their submarines - the infamous U-boats. The seas off Cornwall became a war zone, where hundreds of merchant ships were sunk by U-boats, and thousands of seamen died.

One ingenious response to the threat of the U-boats was the introduction of 'decoy ships'. These were armed merchant ships with hidden guns. Their purpose was to attract U-boats to surface by appearing unarmed. When the U-boat surfaced to attack the apparently defenceless ship, it revealed its position, and the decoy ship would open fire.

The exhibition includes the audio memories of able seaman George Hempenstall who was aboard a decoy ship when it successfully sank a U-boat in August 1915. George recalled : '…. …We fired away at the submarine, as long as there was anything to fire at, we fired at it'. In around 150 encounters, decoy ships sunk 14 U-boats and damaged another 60. It was at some cost as 27 decoy ships were lost from 200 in service.

In September 1917 the British developed the convoy system. Merchant ships travelled in groups with a strong naval escort - this reduced the number of targets and forced the U-boats to attack well-defended convoys. Although merchant ships continued to be sunk, the convoy system reduced losses and more U-boats were destroyed. The battle was won, but the cost was high - around 5,000 ships were sunk worldwide, with the loss of 178 U-boats, and 14,661 merchant seamen on Allied ships lost their lives.

WW1 Militia Troops 7 Gun at Pendennis Castle
Officers and men of a Royal Garrison Artillery unit at Pendennis in WW1 © Royal Cornwall Polytechnic Society


100 years ago the picturesque seaside town of Falmouth became a place of suspicion and mistrust. At the start of the war it became a secure area, where people of foreign origin, or 'aliens' had to be excluded.

Anyone attempting to enter England from the western end of the English Channel was required to report into Falmouth via the port 'Examination Service'. Anyone under suspicion might be questioned by the 'Alien Officer', a Home Office employee empowered to arrest citizens of hostile nations. With links to the intelligence services, he also received tip-offs about suspicious ships and individuals travelling on them and as a result many crew members and passengers were arrested on entry to Falmouth.

When war broke, German residents in Britain came under immediate suspicion, and mistrust extended to people of many other nationalities. Several people were arrested on suspicion of spying but while a few were real suspects, many were ordinary people detained because of their nationality. Most famously the exotic dancer Mata Hari was arrested entering Falmouth on board SS Hollandia on 14 November 1916. Thinking she was the German spy Clara Benedix, she was escorted from Falmouth to London for interrogation. Without evidence against her she was freed but deported once more through Falmouth. Mata Hari was later arrested in France and tried as a spy; found guilty, she was shot in October 1917.

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Black and White photo of Mata Hari in eastern dress
Mata Hari, exotic dancer
'step into englands story