| Description | Extract from Parliamentary proceedings, House of Commons, 15 December 1938. Home Office circular 2/1939 dated 9th an. 1939. Specifications etc in regard to permanent lining of trenches, with specifications and drawing. Home Office ARP department circular No.11/1939 - Permanent lining of trenches. Also circulars 18/1939, 30/1939, 39/1939, 47/1939, 58/1939, 79/1939, 83/1939, 106/1939, 166/1939, 286/1939 - Lining of trenches. |