He returned to the command of the 6th Armoured upon its piecemeal arrival in Italy (the 1st Guards Brigade had already arrived in Italy in February) and commanded it during Operation Diadem, the Fourth Battle of Monte Cassino. On 24 July 1944 he relinquished command of the 6th Armoured, due to a perceived poor performance, over to Major General Gerald Templer, to serve as Assistant Chief of the General Staff from August 1944 to May 1945.