Operation Epsom, or the battle of the Odon,was the first major British offensive to be launched after the D-Day landings, and was a successful attempt to force the Germans to concentrate their armoured units against the British and Canadians, at the eastern end of the Normandy beachhead. The attack was to be carried out by General O'Connor's VIII Corps (11th Armoured, 15th (Scottish) and 43rd (Wessex) Divisions), part of the follow-up force that landing in Normandy in the weeks after D-Day. O'Connor had some 60,000 under his command, but most of them were inexperienced troops, for whom Epsom would be their first experience of battle.
Montgomery had originally intended to begin the Epsom offensive on 18 June, but at that point only one of O'Connor's divisions had reached Normandy. On the following day the 'Great Storm' began, and for three days the Allies were only able to land a fraction of the supplies they needed. This delay would play a major role in the upcoming offensive, for on 18 June the Germans had almost no reserves, and a determined British attack may well have cracked their line open, but by 26 June the powerful 2nd SS Panzer Corps, led by the experienced General Hausser, had finally reached Normandy.
The main purpose of Operation Epsom was to draw the German armour onto the British and Canadians, and to prevent Rommel from moving any of his panzer divisions west towards the American front, where preparations were underway for Operation Cobra, the breakout from the beachhead. This was even more important by late June than it had been in the middle of the month, for Rommel intended to use the 2nd SS Panzer Corps to launch a major attack of his own, at the point where the British and American armies joined, which might had badly disrupted the plans for Cobra.
In order to achieve this objective Montgomery decided to use O'Connor's corps for an attack to the west of Caen. The 15th (Scottish) Division was to attack across the Odon and capture the higher ground between the Odon and the Orne. The 43rd (Wessex) Division was to support this attack, and the 11th Armoured Division was to advance attack south-east across the Orne and cut the Caen-Falaise road. On the day before Epsom was due to start the 49th Division (XXX Corps) was to capture Rauray ridge east of Caen. These two attacks would threaten Caen with envelopment and pose a threat to Paris.
Even after the end of the great storm the weather failed to cooperate with Epsom. The 49th Divisions advance on 25 June was held up by thick mist, and heavy rain on the night of 25-26 June meant that the air bombardment had to be cancelled. Despite this Montgomery knew that he couldn't afford to postpone the offensive, and so early on 26 June 500 guns began a three hour long artillery barrage, supported by naval guns from the fleet off the beaches. Although some damage was done by this bombardment, the German defensive lines were several miles thick by this date, and troops from the 12th SS Division were able to move to the threatened part of the lines, where they put up one of the most determined defensive efforts of the entire Normandy campaign. The rain also helped the defenders by turning the ground in the cleared corridors through the German minefields into mud, greatly slowing down Allied armour and vehicles. At the end of the day the Scots had not yet captured Cheux, in the centre of their front, and in most places were less than half way to the Odon, although on the left they had advanced further, and had reached the railway from Caen to Villers-Bocage.
The Allies were disappointed with their progress, but they would have been much happier if they had known how much despondency they had caused on the German side of the lines. General Dollman, commander of the Seventh Army, was aware that any Allied foothold south of the Odon threatened his entire line, while by the end of the day Sepp Dietrich was warning him that if he was not sent reinforcements then the line would break on both sides of Cheux. During the day Dollman twice ordered the 2nd SS Panzer Corps (Hausser) to move towards Caen, on both occasions cancelling the order. By the end of the day Rommel had been forced to abandon his planned offensive, and ordered Hausser to use his corps, with reinforcements from troops already in the area, to prop up the line on the Odon.
This order was cancelled once again on the morning of 27 June, when after a quiet night Dietrich reported that he had committed 70 tanks in a counterattack, but the German armour was defeated by Allied anti-tank defences, and by the end of the day the Scots had captured a bridge over the Odon, and by the following morning the tanks of the 11th Armoured Division were across the river. This potential breakthrough came at exactly the wrong time for the Germans. Von Rundstedt had finally plucked up the courage to demand that Hitler give him the authority to make major adjustments to the front line if they were required – in effect to abandon territory to create a shorter or stronger line. Hitler responded by summoning von Rundstedt and Rommel to Berchtesgaden, and by the morning of 28 June both men were on their way east, not to return until 30 June. This left Dollman in command in Normandy, and with Allied tanks across the Odon he once again ordered Hausser to throw his tanks into the battle. Hausser wanted to fight a containing battle over the next two days to give his corps a chance to assemble properly, but Dollman ordered him not to delay, and then shortly after that died, either of a stress-induced heart attack or by committing suicide.
During 28 June the British managed to capture the northern slopes of Hill 112, their main objective for the day, but they were unable to secure the summit of this hill, which to a certain extent dominated the local area. At the same time Allied reconnaissance aircraft reported sighting large German motorised columns travelling in daylight, a most unusual sight since D-Day, and General Dempsey, O'Connor's immediate commander, realised that a major counterattack was likely. At this point the British bridgehead over the Odon was very vulnerable. Although a second bridge had been captured by troops on the far side of the river it was still not open to traffic, and the only road from the main bridgehead through the corridor to the Odon was under constant artillery fire. Dempsey decided not to risk any advance towards the Orne, a move that would have almost certainly failed as the attacking troops ran into 2nd SS Corps, and O'Connor was ordered to consolidate his position north of the Odon and prepare to resist a major armoured counterattack. O'Connor correctly realised that the main attack would come from the west, taking advantage of the ridge that ran from Rauray to Cheux, and posted his strongest anti-tank defences on that flank.
Hausser hoped to launch his attack on the morning of 29 June. The 10th SS Division was to attack first, hitting the bridgehead across the Odon. Once this attack was underway the main attack would be launched from the west by the equivalent of two full SS Panzer divisions. Unfortunately for Hausser the skies were clear on 29 June, and his tanks came under constant attack from the air. A number of tanks were destroyed by rocket firing Typhoons, but more importantly the offensive was delayed until well into the afternoon, by which time the Allies had captured a copy of Hausser's plans, and the 11th Armoured Division had moved some tanks onto Hill 112.
The 10th SS Division finally began its attack at 2.30pm, but the main offensive couldn't start until 6.00, and even then only the equivalent of one division was available. The Germans were able to get around 200 tanks into the fighting, but now it was the German's turn to discover how difficult it was to attack in the Normandy countryside. The limited visibility in the bocage meant that much of the fighting took place at very close range, where the technical advantages of the German tanks were largely negated, and even the short range Piat became an effective weapon. By the end of the day the German offensive had failed, those few tanks that had threatened to reach Cheux had been destroyed, and the remaining German troops were under constant artillery bombardment as they attempted to reform for a new attack.
Both Operation Epsom and the German counterattack came to an end on 30 June. On the night of 29-30 June O'Conner withdrew his tanks from Hill 112, which fell back into German hands during the day, and remained in German hands until late July, but by the end of the day Hausser, who had now succeeded to command of the Seventh Army, was forced to tell Rommel that the 1st and 2nd SS Panzer Corps had been forced to suspect their offensive. At the same time the German counterattack had forced Montgomery to abandon any idea of a prolonged offensive west of Caen, or of crossing the Orne on that flank.
Operation Epsom had its main objective. The 2nd SS Panzer Corps, a large, well equipped, experienced unit, had been drawn into the fighting around Caen, and was not longer available to take part in any German counterattack or to reinforce the American front. O'Connor's men had proved that the new British army was just as capable as the experienced troops of the 8th Army, and if anything were more flexible and able to adapt to conditions in Normandy, although they did tend to be too ponderous, operating 'by the book'. Epsom saw some of the most intense fighting of the entire Normandy campaign – the 15th (Scottish) Division, which was in action for almost the entire campaign between Epsom and VE day, suffered 25% of their total casualties during the four days of fighting on the Odon.
Epsom had been more successful than most Allied commanders realised at the time. The determined nature of the German resistance meant that very few people on the Allied side realised how brittle the German line in Normandy had become, while the failure to capture Caen began to dog Montgomery, and caused an increasing level of stress in his relationships with Eisenhower and with senior RAF commanders that would come to a head in mid to late July, just as the Allies finally broke the German lines.