Every year on Ascension Day, the Choir ascends the 163ft Chapel Tower and sings the Ascension Day Carol.
This custom dates from 1902 and was begun by the then Director of Music, Cyril Rootham, following a conversation with Sir Joseph Larmor. Sir Jospeh was insistent that a choir singing from the tower would not be heard from the ground. Rootham was keen to prove him wrong and saw Ascension Day as the perfect time to do it.
Without telling anyone in College, the Choir ascended the tower and as the clock finished striking noon, they started to sing an Ascension Day Carol. To Rootham's delight, he saw Sir Joseph open his window in the court below to see where the music was coming from. The event proved popular and since then it has been repeated every year.