A three-week restoration project is underway to care for the 15 cannon and guns at St Mawes Castle in Cornwall, which range in date from the mid-16th to 19th centuries.

English Heritage, who care for the Tudor fort, will be conducting work on these impressive historical weapons until the end of June.

St Mawes Castle is one of the best-preserved and most elaborately decorated of the 30 coastal fortresses commissioned by Henry VIII under threat of French and Spanish invasion in the 1540s.

Today, it boasts a substantial collection of cannon and guns, collected and donated since the military finally vacated the castle in 1956.

Around half of the guns are on loan from the Royal Armouries. The star of the collection is the Alberghetti gun, a mid-16th century bronze ‘Saker’ which was found off the coast of Devon in 1975. The Saker gets its name from the Italian gun maker Sigismondo Alberghetti, whose initials are on the barrel of the gun under a decorative coat of arms.

Volunteers learning maintenance skillsVolunteers learning maintenance skills (Image: Emily Whitfield-Wicks)

Inside the castle keep there are six cast iron cannon, including four dating from the late 18th century - each engraved with the royal cipher of King George III - plus two replica guns mounted on wooden trestles, showing how the castle would have been set up in times of war.

In the 1850s, a Grand Sea Battery for eight-inch guns and a new ammunition store were built in the castle grounds and a cannon from the early 19th century is now on display there. A further five cannon of the same age stand in a row (or ‘saluting battery’) nearby, looking expectantly out to sea.

English Heritage carries out an annual programme of cannon maintenance at its sites across Cornwall, with enhanced work taking place at St Mawes Castle this year.

Exposure to salt in the air and high UV light levels caused by the castle’s seaside location means that the cast iron cannon and wooden carriages holding them deteriorate more rapidly than elsewhere.

Nicki, Tim, Dave and Esther work together to repaint a cannon and restore its carriage (Image: Emily Whitfield-Wicks)

After expert assessment, each cannon will be lifted out of its wooden carriage and then any exposed metalwork will be rubbed down to remove areas of corrosion and then repainted. The paint, which has been chosen carefully after scientific research, also forms a protective layer on the metal to prevent further corrosion in the future.

The Alberghetti gun will be treated with hot wax instead of paint as it is the only cannon made from bronze at the castle. The wooden carriages on which the cannon are mounted will also be washed and treated with a compound to prevent wood root and insect attacks.

David Guest, St Mawes Castle manager, said: “We’re very proud of the cannon we have on display here, so the team have been excited to see this work take place – and it’s proving a fascinating watch for visitors too.

“The cannon are heavy but surprisingly brittle so need to be handled very carefully to ensure they’re not damaged. Make sure to come to the castle before the end of the month if you want to see this conservation in action.”

Training of staff and volunteers in regular cannon maintenance is currently taking place alongside the project.