The family returned home once for the Lambeth Conference in 1897, and Bernard and his brother Harold were educated for a term at The King's School, Canterbury. In 1901, Bishop Montgomery became secretary of the Society for the Propagation of the Gospel, and the family returned to London. Montgomery went to St Paul's School and then the Royal Military Academy, Sandhurst, from which he was almost expelled for setting fire to a fellow cadet during a fight with pokers. On graduation he joined the 1st Battalion, The Royal Warwickshire Regiment in September 1908 as a second lieutenant, first seeing service in India until 1913. He was promoted to lieutenant in 1910.