During the twentieth century, The Leys grew significantly and by 1930 the number of pupils had reached 271. During World War II, the school temporarily moved to the Atholl Palace Hotel in Pitlochry, Scotland, returning to Cambridge in 1946. During the Cold War, the school was designated the auxiliary headquarters to the Regional Seat of Government for Cambridge in time of war. Today the majority of the pupils are boarders and since the admission of girls to the Sixth Form in the 1980s, the school has become fully co-educational. It now accepts pupils from the age of eleven, rather than the age of thirteen as it was before.