Siege of Cuddalore

On 13 June, Stuart decided to attack the redoubt in front of the fort in order to press the allies harder within Cuddalore itself. The assault took place at four in the morning, granting the British army an element of surprise. Eventually, the allies were driven from their principal defences and the last allied counterattack was defeated. By mutual consent, a cessation of firing took place. The allies suffered serious losses of nearly 500 casualties. Stuart's forces also suffered heavily: more than 900 British, Hanoverian, and Sepoys were killed or wounded. Though significantly weakened, Stuart continued to besiege Cuddalore proper and prepared for further reinforcements from the sea.

Key naval support for the British was interrupted on 20 June by the arrival of a French fleet under the Bailli de Suffren, which met the British fleet in a naval battle and forced it to withdraw to Madras. Suffren, with this advantage, was able to land 2,400 soldiers, marines, and sailors in support of de Bussy's garrison, resulting in nearly equal-sized forces.

De Bussy's additional reinforcements now had enough men to launch a sortie on the British siege works. Stuart, aware of the newly arrived French reinforcements, prepared for a major attack. On 25 June, the French made repeated sallies on the British lines. Despite some initial progress, the French were not able to press their advantage; Stuart was able to counterattack and repel the remaining French assaults. De Bussy called off the attack after realising no progress had been made at a considerable cost. The assault was a disaster, and De Bussy had lost a great opportunity in defeating the besiegers, especially with the reinforcements he had received. French morale plummeted as they had lost the advantage in numbers and the balance had swung back in favour of the besieging British. The British had no more than 23 men killed and wounded, while De Bussy's attacking force had 450 killed and wounded with another 150 taken prisoner. A number of French officers were captured including the leader of the assault, the Chevalier de Dumas, who was captured unwounded. Among the French prisoners was a young sergeant in the French marines who was also wounded and had landed from Suffren's squadron on 20 June; Jean Bernadotte became a Marshal of France and, more famously, was later crowned the King of Sweden.

The siege continued for another five days. Both sides were weakening from disease and growing casualties, but Stuart's forces suffered more heavily than De Bussy's. Stuart wrote letters to the Madras government asserting that he had been abandoned. De Bussy planned another attack by a more circuitous route directed at the main camp of the British forces, but this attack was not carried out before a British frigate arrived on 30 June with news of a preliminary peace between France and Britain.