Horne enrolled at the London School of Economics in October 1925, where his tutors included Hugh Dalton and Stephen Leacock; he was dissatisfied with his time at the university and called Leacock "one of the most boring lecturers I ever came across". During the general strike in 1926 volunteers were asked to enlist at the Organisation for the Maintenance of Supplies to take over the essential services; Horne joined, and spent two days driving a London bus before the strike was called off. Through the influence and generosity of an uncle, Austin Pilkington of the Pilkington glassmaking family of St Helens, he was able to enrol at Magdalene College, Cambridge in October 1926. He committed himself to the sporting side of life and represented the college at rugby, and in the relay team alongside the future Olympic gold medallist Lord Burghley. He also played tennis for the university, partnering Bunny Austin. Distracted by his athletic exploits, he neglected his studies and was sent down in December 1927.