The Horton Laboratory was built after the first world war with the building being completed in 1926. It was built to house a Physics Laboratory on the ground floor and a Botany department on the first floor. It functioned in this way until 1967 when the Botany department moved out (to Huntersdale in Virginia Water) and Horton became a building dedicated to Physics.
It continued as the physics department until 1985 and the merger with Bedford College. At that point the building was used for Social Policy and Social Science. That department moved out in 1998 (and moved into the new Arts Building and the Department of Economics moved in. The careers service now occupies part of the building.