
By the evening of 20 May, Guderian’s panzer spearheads had reached Abbeville at the mouth of the Somme, and at this point their line was as thinned out as it ever would be. The Germans were vulnerable to a determined counterattack, but the only one that threatened the speeding panzers was by British tanks at Arras on 21 May. The Allies inflicted a stinging reverse on the SS Totenkopf division, but they quickly found themselves blocked by Rommel’s panzers. After a brisk battle, the British were driven back to their original positions and threatened with encirclement.