Butler attended Brockhurst preparatory school but refused to attend Harrow, where many of his family had been educated. He failed to win a scholarship to Eton, and so he attended Marlborough College. He left Marlborough at the end of 1920, a week after his 18th birthday, and spent five months in France with a Protestant pastor in Abbeville. He returned briefly to England to sit the exams for Pembroke College, Cambridge, where in June 1921 he won an exhibition worth £20 per annum (around £1,000 at 2014 prices), then returned to France to be tutor to the son of Robert de Rothschild. His plan at this stage was to enter the Diplomatic Service.