Small and Mighty: Flat Holm at War

This event forms part of our National Lottery Heritage Fund project Flat Holm – A Walk Through Time

Date and Time
Date(s) - October 20, 2022
12:30 pm-4:30 pm

This special guided tour is a fantastic opportunity to learn about the role this tiny island fortress has played in defending the realm across two centuries. Hear at first hand from military expert Dr Jon Berry about Flat Holm’s military remains and wartime life on this fascinating Welsh island.

Transport by fast Rigid Inflatable Boat boat leaves from Barrage South departure point in Cardiff Bay at 12:30 and returns to Cardiff Bay at 16:30. This is the landing stage immediately in front of the Custom House restaurant, adjacent to Cardiff Barrage Pay and Display Car Park. Postcode is CF64 1TT. Note – a free day parking permit will be provided on arrival.

Please make sure you allow plenty of time to arrive as the boat will leave precisely on time and will not be able to wait for late arrivals.


£50 – this includes your return boat trip from Cardiff Bay, landing fees, and the guided tour.


Please note that boat transport to the island is provided by a third party and you must ensure that you can meet their terms and conditions before making a booking – see


The island of Flat Holm lies some four miles south of Cardiff in the Bristol Channel and was called upon in the nineteenth and twentieth centuries to help defend the Realm against external threats.  The Victorian defences formed part of an arrangement of ‘stone frigates’, and Flat Holm’s intriguing Moncrieff disappearing guns helped to defend the upper reaches of the Bristol Channel and the Severn estuary.  The gun batteries and the accommodation for the soldiers are well preserved and visitors will be able to understand how the defences operated, see where the guns hid and how the soldiers lived their lives on the island.

The intensification of the threat of aerial bombardment was a significant characteristic of the Second World War, and a new set of combined coastal and anti-aircraft gun batteries were installed together with powerful searchlights, radar, and accommodation forming part of the ring of defences around the strategically important port of Cardiff.  Visitors will learn how these worked in conjunction with other defences to offer protection.

The sheer concentration of military defences that survive in such good condition in such a small space is remarkable, and visitors will be able to appreciate and understand why these were built, how they functioned, why they were eventually abandoned and how they are managed now as lasting legacies of two of the defining events of the nineteenth and twentieth centuries.


Jon Berry is Cadw’s Senior Inspector of Ancient Monuments and Archaeology.  He has a long-standing interest in modern conflict archaeology and is one of the leading experts on this important part of the history of Wales.  His PhD is in the Second World War anti-invasion defences of Wales.



Please ensure that you are wearing suitable clothing for spending several hours outdoors on an exposed island and footwear that is suitable for uneven and slippery surfaces. Waterproof jacket and trousers are recommended for the boat crossing and any delicate equipment should be protected from water and shock (e.g., cameras in cases). Please note that due to restricted space in the boat you should try and keep kit to a minimum.

There will be time at the end of the tour to enjoy refreshments in our small pub “The Gull and Leek” – please bring cash for purchasing items as we are unable to take card payments.

HOW TO BOOK – For further information and bookings please email 

Places are limited to 11 people due to capacity of the boat.

Leader details


Price :

October 20, 2022 12:30 pm.

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