Series Number Id: UNKNOWN. Sheet number: [36 SW]. First Army secret defence map. At head of map in red overprint: Secret. "[First] Field Survey Co., R.E. 5741 [numbers crossed out and replaced with blue overprint] 5865." Grey squared base map. German front in red; British front and rear defence lines in red and blue. Includes "Reference" to wire, defended localities [hatched areas], assembly points, and posts.
Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC23; envelope_number: 703.
Series Number Id: UNKNOWN. Sheet number: [36 SW]. First Army secret defence map. At head of map in red overprint: Secret. "Showing zones of defence: forward zone [red]; battle zone [blue]; rear zone [green]". "[First] Field Survey Co., R.E. 5741 [numbers crossed out and replace with blue overprint] 5865." Grey squared base map. German front line in red. British front and rear defence lines in red and blue; zones of defence in pink, bale blue and pale green. Includes "Reference" to wire; defended localities (hatched areas); assembly points; posts.
Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC23; envelope_number: 702.
Series Number Id: UNKNOWN. Sheet number: part of sheet 36. First Army secret defence map. "[First] Field Survey Co., R.E. 5740 [numbers crossed out and replaced with blue overprint] 5839." Grey squared base map. German front line in red; British front and rear defence lines in red and blue; zones of defence in pink, pale blue, and pale green. Includes "Reference" to defended localities [hatched areas], assembly points, posts and wire., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC23; envelope_number: 701.
Series Number Id: UNKNOWN. Sheet number: [5]. Battle of the Lys, April 1918. "Field Survey Coy R.E. (8142) 26-1-18". Grey base map; overprint in black, red, and green. "Secret" in red overprint. Shows Front Line (east of Ypres and Kemmel, west of Merville, and whole of Second Army front from Belgian area to First Army area, as far west as Saint-Omer). Corps defensive zone in green; lines of defence in black; Corps roads in red. Manuscript in top margin: G.S.O.1 (T)., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC27; envelope_number: 794.
Series Number Id: UNKNOWN. Sheet number: parts of sheets 28, 29, 36. Secret, rear defence lines, April 1918. "Secret" in red overprint. "[4th] Field Survey Coy R.E. (8142) 26-1-18 [numbers stroked out with black overprint and followed with] (8729) 30-4-18." Grey base map; overprint in black and red. Rear defence lines shown in black and red., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC19; envelope_number: 594.