The Consortium of Local Authorities Special Programme (abbreviated and more commonly referred to as CLASP), was formed in England in 1957 to combine the resources of Local Authorities with the purpose of developing a prefabricated school building programme. Initially developed by Charles Herbert Aslin, the county architect for Hertfordshire, the system was used as a model for several other counties, most notably Nottinghamshire and Derbyshire. CLASP's popularity in these coal mining areas was in part because the system permitted fairly straightforward replacement of subsidence damaged sections of building.