Dempsey), to secure the city and then form a front line from Caumont-l'Éventé to the south-east of Caen. The intention was to acquire space for airfields and to protect the left flank of the US First Army (Lieutenant General Omar N. Bradley), while it fought the Battle of Cherbourg. Possession of Caen and its surroundings would give the Second Army a suitable staging area for a push south to capture Falaise, which could be used as the pivot for a swing left to advance on Argentan and then towards the Touques River. Hampered by congestion in the beachhead, which delayed the deployment of its armoured support and forced to divert effort to attack strongly held German positions along the route to the town, the 3rd Infantry Division was unable to assault Caen in force on D-Day and was stopped short by the 21st Panzer Division. Follow-up attacks failed as German reinforcements arrived. Abandoning the direct approach, Operation Perch—a pincer attack by I and XXX Corps—was launched on 7 June, to encircle Caen from the east and west. I Corps, striking south out of the Orne bridgehead, was halted by the 21st Panzer Division and the attack by XXX Corps west of Caen was stopped in front of Tilly-sur-Seulles by the Panzer-Lehr-Division. To force Panzer-Lehr to withdraw or surrender and to keep operations fluid, part of the 7th Armoured Division pushed through a gap in the German front line near Caumont and captured Villers-Bocage. The Battle of Villers-Bocage led to the vanguard of the 7th Armoured Division being ambushed and withdrawing from the town but by 17 June, Panzer Lehr had also been forced back and XXX Corps had taken Tilly-sur-Seulles. Another attack by the 7th Armoured Division and other offensive operations were abandoned when a severe storm descended on the English Channel on 19 June. The storm lasted for three days and further delayed the Allied build-up. Most of the convoys of landing craft and ships already at sea were driven back to ports in Britain; towed barges and other loads (including of floating roadways for the Mulberry harbours) were lost and 800 craft were left stranded on Normandy beaches until the spring tides in July. Planning began for a second offensive, Operation Dreadnought, from the Orne bridgehead by the British VIII Corps (Lieutenant-General Richard O'Connor), outflanking Caen from the east. Dreadnought was cancelled following objections from O'Connor after studying