While the lines were three-quarters of a mile apart the cannonading began on both sides, and was continued with deadly precision and effect until noon, when Lally sent forward a small party of his European cavalry to charge the British left. A few companies of sepoys and two guns sent forward by Coote soon drove these in rear of their own army, and as the forces still continued approaching, by one o'clock the roar of musketry became general along both lines from flank to flank, and that broad plain on which a cloudless sun was shining became shrouded in snow-white smoke.
Undaunted by the cowardice of his cavalry, the hot-blooded Lally now threw himself into the line of his infantry, and at the head of the Regiment of Lorraine fell impetuously upon the British. Colonel Coote was on foot and at the head of his own regiment to receive them.
After giving and receiving two discharges of musketry, the Regiment de Lorraine rushed on with a fury that threatened to sweep all before it. Lally was in front, sword in hand; the bayonets crossed—the British line was broken; but though a momentary confusion followed, it was not driven back. A series of bloody single combats ensued, with the charged bayonet and clubbed musket; but these were of brief duration; for in three minutes the Regiment of Lorraine was broken in turn, routed, and driven back in headlong confusion, over a field strewed with their own killed and wounded. The explosion of a tumbril in rear of the French line created an additional confusion, of which Coote lost not a moment in taking advantage.
He ordered Major Brereton to advance with the regiment of Colonel Draper (who had returned to Europe for the benefit of his health), and by wheeling to the right to fall on the French left, and seize a fortified post which they were on the point of abandoning.
This service was performed with the utmost bravery; the French left was routed and driven pell-mell upon their centre. Draper's regiment was the 79th, not the present Cameron Highlanders, but a corps which was disbanded in 1763. All had now become confusion among the enemy, but the gallant and accomplished Brereton fell mortally wounded.
"Follow—follow!" he exclaimed to some soldiers who loitered near him; "follow and leave me to my fate!" He soon expired; led by Major Monsoon, the regiment advanced impetuously on, and after a vain and desperate attempt, made by the Chevalier de Bussy, with Lally's regiment, to repel it, the French and their allies were completely routed in every direction by two o'clock in the afternoon. The Regiment de Lally was almost cut to pieces; the horse of Brigadier-General M. de Bussy was shot under him, and he was taken prisoner by Major Monsoon, to whom he surrendered his sword.
Lally having brought up his fugitive cavalry, formed them in rear of his infantry, and enabled these to make a secure though precipitate retreat, leaving on the field a thousand men killed and wounded, with fifty prisoners, including the Marquis de Bussy, Quartermaster-General le Chevalier de Gadville, Lieutenant-Colonel Murphy, three captains, five lieutenants, many other officers, and twenty-two pieces of cannon.
Coote lost 260 killed and wounded. Among the former was the gallant Brereton. Maréchal Charles Grant, Vicomte de Vaux, affirms that the losses were equal on both sides.
Covering the foot by the cavalry, Lally conducted his routed forces with considerable skill and good order to Pondicherry, while Coote lost not a moment in pursuing the advantage he had gained. Dispatching the Baron Vasserot towards that place with 1000 horse and 300 sepoys, and with orders to ravage and lay waste all the French territory in and around it, he advanced in person against Chittipett, a small town and fort in the Carnatic, which, after a defence of two days, was surrendered on the 29th January, 1760, by the Chevalier de Tillie, who with his garrison remained prisoners of war.
On the 2nd February he reduced the fort of Timmary on the Coromandel coast, and pushing on to Arcot, the capital, opened his batteries and dug his approaches within sixty yards of the glacis. The garrison, which consisted of 250 French with 300 sepoys, defended the place until the 10th, when they surrendered as prisoners of war, delivering up twenty-two pieces of cannon and a large store of warlike munition.