​​​​80,000 men were allocated to this Operation. This included 60,000 from O'Connor’s 8th Corps and 20,000 from Bucknall’s 30th Corps and the 1st Canadian Corps. Nearly 600 tanks and 700 guns were mobilised. It was the first major operation of General Montgomery after the 6 June landings.

​The operation of the British Second Army was planned on 22 June 1944 but launched on 26 June because the buildup was hampered by the ‘Great Storm’ that raged in the English Channel. This caused significant damage to the artificial harbour at Arromanches-les-Bains. The plan was to cross the Odon and Orne River valleys to the southwest of Caen.

​It was the men of the 15th Scottish Infantry Division who launched themselves into action first, behind an artillery barrage known as a creeping or rolling barrage.

The villages of Saint-Manvieu, Norrey, Fontenay-le-Pesnel and Cheux were totally in ruins but were liberated on the morning of 26 June. The next day, 27 June, the fighting continued in the Odon valley. Tourville, Mondrainville and Rauray were liberated.

The bocage (Normandy hedgerows) was found to be a good ally to the German defenders. Thousands of British soldiers fell under the fire of mortars and rocket launchers, for the capture of a narrow corridor of 8km by 3km beyond the Odon. This became known as the ‘Scottish corridor’. 2,500 men of the 15th Scottish Infantry Division were lost during operation Epsom.

​To break the British salient at Hill 112 held by the 11th Armoured Division, the German 2nd SS Panzer Corps had recently arrived from Poland. They conducted counter attacks on both banks of the Odon from 29 June.

​On the evening of 29 June, the German divisions were repulsed by the combined actions of the Royal Air Force, the British Navy and the 15th Scottish Infantry Division. Hill 112, a strategic highpoint, was not captured by the 11th Armoured Division with only a small salient over the river Odon being captured. The village of Mouen was liberated in the morning.

​The next day, 30 June, Montgomery ended Operation Epsom, fearing a larger German counterattack. The second British attempt to capture and liberate Caen had failed. The human toll was very heavy with 4,000 men of the 8th Corps either killed, wounded or missing in a span of 5 days.