After the failure of British tanks in the thick mud at Passchendaele, Colonel John Fuller, chief of staff to the Tank Corps, suggested a massed raid on dry ground between the Canal du Nord and the St Quentin Canal. General Sir Julian Byng, commander of the Third Army, accepted Fuller's plan, it was originally vetoed by the Commander-in-Chief, Sir Douglas Haig. After the failure to break through at Ypres, Haig changed his mind and ordered a massed tank attack at Artois. Launched at dawn on 20th November, without preliminary bombardment, the attack completely surprised the German Army defending that part of the Western Front. Employing 476 tanks, six infantry and two cavalry divisions, the British Third Army gained over 6km in the first day. Progress towards Cambrai continued over the next few days but on the 30th November, 29 German divisions launched a counter-offensive. By the time that fighting came to an end on 7th December, 1917, German forces had regained almost all the ground it lost at the start of the Cambrai Offensive. During the two weeks of fighting, the British suffered 45,000 casualties. Although it is estimated that the Germans lost 50,000 men, Haig considered the offensive as a failure and reinforced his doubts about the ability of tanks to win the war.