Trefusis proved a popular and effective Commanding Officer, who led the battalion through the battles of Neuve Chapelle and Festubert (where the Irish Guards again lost heavily), and during the trench and mine warfare around Ypres and Cuinchy. In August, 'the C.O., Colonel Trefusis, was telephoned word that he was to command the 20th Brigade and was pathetically grieved at his promotion. He hated leaving the Battalion which, after eleven months of better or worse, he had come to look upon as his own' ("Kipling").