Over the following days, the Germans established bridgeheads over the river and canal and continued to press the BEF from all sides. On 26 May, with the BEF completely surrounded, and the military situation in Flanders further deteriorating, the decision was made to evacuate the BEF from Dunkirk, the only remaining port in British hands. With the evacuation order given, the remnants of the 23rd Division began withdrawing towards Dunkirk with the men always under the threat of or actual attack from the air. During this stage of the campaign, the division was assigned to III Corps for a 48-hour period, before being placed under II Corps for the remainder of the campaign. A detachment of 100 men formed a rearguard to defend bridges over the La Bassée Canal, resulting in their eventual death or capture. On the 28th, the division reached Killem Lynde, Marley Force having conducted further rearguard duties before being relieved by other British forces. Here, all remaining transport and unnecessary baggage was destroyed. On 30 May, the division entered the final Dunkirk perimeter and moved into a defensive position behind the 50th (Northumberland) Motor Division. Marley Force surrendered all their Bren guns to the 50th Division, and around 100 men from the 11th DLI went into the frontline to reinforce their sister battalion, the 8th DLI.