In December 1994 the CBA was commissoned by English Heritage's Monuments Protection Programme (MPP) to undertake a national survey of documentary records for several classes of 20th century defence sites. By systematic scanning of material held in the Public Record Office at Kew, the purpose of this work is to establish as far as possible the original populations, distributions, design principles and context of the works constructed……Fieldwork will follow the formal launch of the project in April 1995 and run for several years with the primary purpose of answering questions raised by archival research. (1) See E805 for Field Survey.