had been cut. The Germans used infiltration tactics to get among the British, who were beaten back. The heaviest fighting was in the 5th Division's sector. Still on 27 May, Brooke ordered the 3rd Division commander, Major-General Bernard Montgomery, to extend his division's line to the left, thereby freeing the 10th and 11th Brigades, both of the 4th Division, to join the 5th Division at Messines Ridge. The 10th Brigade arrived first, to find the enemy had advanced so far they were closing on the British field artillery. Between them, the 10th and 11th Brigades cleared the ridge of Germans, and by 28 May they were securely dug in east of Wytschaete. That day, Brooke ordered a counterattack. This was to be spearheaded by two battalions, the 3rd Grenadier Guards and 2nd North Staffordshire Regiment, both of Major-General Harold Alexander's 1st Division. The North Staffords advanced as far as the Kortekeer River, while the Grenadiers reached the canal itself, but could not hold it. The counterattack disrupted the Germans, holding them back a little longer while the BEF retreated. Action at Poperinge The route back from Brooke's position to Dunkirk passed through the town of Poperinge (known to most British sources as "Poperinghe"), where there was a bottleneck at a bridge over the Yser canal. Most of the main roads in the area converged on that bridge. On 27 May, the Luftwaffe bombed the resulting traffic jam thoroughly for two hours, destroying or immobilising about 80 percent of the vehicles. Another Luftwaffe raid, on the night of 28–29 May, was illuminated by flares as well as the light from burning vehicles. The British 44th Division in particular had to abandon many guns and lorries, losing almost all of them between Poperinge and the Mont. The German 6. Panzerdivision could probably have destroyed the 44th Division at Poperinge on 29 May, thereby cutting off the 3rd and 50th Divisions as well. The historian and author Julian Thompson calls it "astonishing" that they did not, but they were distracted, investing the nearby town of Cassel. Belgian surrender Gort had ordered Lieutenant General Adam, commanding III Corps, and French General Fagalde to prepare a perimeter defence of Dunkirk. The perimeter was semicircular, with French troops manning the western sector and British troops the eastern. It ran along the Belgian coastline from Nieuwpoort in the east via Veurne, Bulskamp and Bergues to Gravelines in