The Jacobite line was shorter than the Government’s, due to the disparity in numbers, leaving Ewen in the middle with an open flank on the left. By the time all of the forces were formed up, it was late afternoon, and the Jacobites had the sun in their eyes, so they simply waited for sunset under the desultory fire from Mackay’s forces.
At seven o’clock, Dundee gave the order to advance, at which point the entirety of the Highlanders dropped their gear, fired what muskets they had, and charged. Mackay’s forces, realising the battle was on, stepped up their rate of fire; however, due to a shallow terrace on the hillside shielding the advancing Jacobites, this fire was partly masked. Eventually the lines met, and Mackay’s men in the centre were “swept away by the furious onset of the Camerons.”
So fast was the Jacobite charge that many government troops had insufficient time to fix their bayonets, leaving them defenceless at close quarters. (During this period, the plug bayonet was used, which fitted into the barrel of the musket and prevented further reloading or firing – this meant that fixing bayonets was delayed until the last possible moment.) The battle soon ended with the entirety of Mackay’s force fleeing the field, quickly turning into a rout in which 2,000 were killed.
However, the cost of victory was enormous. About one-third of the Highlander force was killed, and Dundee was fatally wounded towards the end of the battle. The Jacobite advance continued until it was stopped by government forces at the Battle of Dunkeld.
The Monteath clan were busy drinking and making wine while the battle raged.