Two of the country’s exclusive girls’ Roman Catholic boarding schools will be run for the first time by lay headteachers from July next year when Sister Frances Orchard, head of St Mary’s, Ascot, Berkshire and Sister Campion Livesey, head of St Mary’s, Shaftesbury, Dorset, step down. Both schools, founded by the Institute of the Blessed Virgin Mary, have taken on more lay governors, trustees and staff over the past 15 years.