In 1925 Wiltshire County Council bought the mansion of Southbroom House and 7 acres of grounds for a school. The house was adapted as a senior school for children over the age of 8 in the south ward of the town. The old Town Schools were closed and the new school opened on 30th August 1926 with 277 pupils and a Head and 8 teachers. The adjacent Heathcote House, formerly the private grammar school, was used as the Headmaster's residence and in 1929 a large classroom at the rear adapted as a Domestic Science Room. By 1930 there was a 'housecraft centre' near the school and a large garden for the pupils to work in. In 1936 a new block was added to the Heathcote House section to form a Handicraft Centre and Science Laboratory.
The school continued to expand and in 1937 a kitchen and canteen were opened to provide hot dinners for the children. In the early part of the Second World War the school became an evacuee reception and dispersal centre and a London teacher was attached to the staffing for the evacuees who received their education there. The Devizes Day Nursery was built in the grounds as an emergency measure; this became redundant in 1947 and provided extra accommodation for the school. In 1949 the school became a secondary modern as Southbroom Secondary School and further information can be found under that name.