On the 20 November 1917, the allies smashed a seven-mile wide, four-mile deep hole in the Germans’ toughest defences near Cambrai. In six hours, they had advanced further than they had in three months at Passchendaele. Yet by 1 December, after a German counter attack, both sides held roughly the same territory as at the beginning of the bloody battle. So, can we truly say this battle was a success?