channel ports. Attacking to the south-west was rejected and OKH ordered to capture Boulogne and Calais, about away. Apprehension of another Allied attack caused Rundstedt to order to remain in position, the XLI Corps (Reinhardt) sent a division eastwards as a precaution and Kleist diverted the 10th Panzer Division and parts of the 1st Panzer Division and the 2nd Panzer Division from the XIX Corps (Guderian) to hold the bridgehead over the Somme, which slowed the advance to Dunkirk from the beginning. The XIX Corps attacked again at on 22 May but was still hampered by a "near paralysis" in the German command, Rundstedt ordering that the instructions from OKH were to be ignored and the advance on Boulogne and Calais would have to wait. At Rundstedt countermanded his own order but for five hours, the panzers had waited on the Amache river. In 2005, Frieser wrote that Allied planning was notable for its failure to cut the panzer corridor when there were insufficient German motorised divisions to consolidate behind the panzer divisions and the non-motorised divisions were several days' march away. The corridor was only wide at Arras and vulnerable to a pincer movement; The Allies could have achieved a Clausewitzian counter-encirclement and cut off the panzers on the channel coast. Halder had been willing to run the risk, because of the incapacity of the Allies to achieve a fast tempo of operations. The Allied attack was contained because Rommel improvised a gun line of anti-tank guns and anti-aircraft guns, that managed to stop some of the lighter British tanks; the infantry tanks, particularly the Matilda IIs, proved very difficult to knock out with the standard 37 mm anti tank gun. Rommel also used wireless to order another gun line quickly to be set up with artillery and several anti-aircraft guns much further back, which knocked out 24 tanks in a few minutes on the flat ground between Mercatel and Tilloy. Just after Junkers Ju 87 of I and VIII arrived and made on the retiring tanks by Rommel ordered Panzer-Regiment 25 to return and cut off the British tanks but south of Duisans it met French tanks covering the British right flank and only pushed through after a long and costly engagement. When the German tanks had broken through a British anti-tank gun line, between Duisans and Warlus, the British tanks had already returned; the British attack had