The imposition of an authoritarian governance model by the French in Lefkada prompted the locals to seek assistance from the British Empire, aiming to liberate themselves from this oppressive rule. Responding to the call, the British decided to intervene militarily in order to free the island from French control.
Consequently, in 1810, a British expeditionary force led by General Oswald and Major-General Church embarked on the task of capturing the fortress of Agia Mavra. On March 9, the British fleet dropped anchor in the bay of Drepano, and the following day, troops consisting of 4,000 British and Greek soldiers landed on the shore.
Under the command of General Oswald, the British military leader, the Greeks, led by Major Church and the military commander Kolokotronis, were ordered to seize all the French gun emplacements surrounding the fortress. With the capture of the final position in the Gyra area, the siege of the fortress began on April 8.
Despite a staunch defense, the defenders of the castle gradually lost faith due to a lack of reinforcements and supplies. After 8 days of a tight siege, the French garrison commander realized that resistance was futile and surrendered the fortress.
On April 17, General Oswald entered the town without raising the British flag, aiming to convey that the British had come as liberators for the people of Lefkada, rather than as conquerors.
In contrast to the Ottomans and Venetians who showed particular zeal for the defensive fortification of the fortress, the British dealt minimally with this specific aspect. They maintained the existing fortifications and carried out limited-scale interventions for their modernization. The main ones included the adaptation of cannon embrasures to meet the firing needs of cutting-edge firearms and the addition of rotating platforms for cannons on top of the bastions.
In November 1815, with the Treaty of Paris between Russia and Great Britain, the Ionian Islands became formally independent under the name “United States of the Ionian Islands,” under British Protection. During this period, significant changes took place, primarily concerning the construction of infrastructure both within and outside the fortress.
Internally, efforts were directed towards enhancing the living conditions of the garrison, given the castle’s function as a military camp at the time. Surrounding the buildings, durable paths were crafted with pebble and cobblestone, and ramps leading to the battlements were paved for the movement of wagons and soldiers. Additionally, a more sophisticated drainage and water supply network was established. The old structures underwent renovation, and, in addition, four barracks, officer clubs, a hospital, prisons, and a lighthouse were erected. Furthermore, the cemetery area was meticulously planned, featuring its own ossuary. The wooden bridges linking the castle to Acarnania and Lefkada were replaced with sturdier stone constructions.
