The new buildings were opened by Her Grace The Duchess of Abercorn in May 1962, and on the same day the then Permanent Secretary to the Ministry of Education announced that a new block would be erected to house the Preparatory Department, and this followed in 1964. In 1974 the girls joined the boys of Foyle College Preparatory Department which moved into these premises in 1974, and so anticipated the later amalgamation under the Foyle and Londonderry College Act of 1976, resulting in the first co-educational grammar school in Derry. The Preparatory Department closed in 2003.