46th Division 200 & 220 (Derby) AA Btys at Derby 276 & 277 AA Btys at Nottingham 42 (Robin Hoods) AA Battalion RE – see above 44 (Leicester) AA Battalion RE – see above 50 (Northamptonshire Regiment) AA Battalion RE – formed in 1937 by conversion of 4th Bn Northamptonshire Regiment 400, 401, 402, 403 AA Coys 32nd Anti-Aircraft Brigade Company, Royal Army Service Corps Battle of Britain and Blitz In 1940 the RE AA battalions were transferred to the RA, and that summer the AA regiments of the RA were redesignated Heavy Anti-Aircraft (HAA) to distinguish them from the new Light Anti-Aircraft (LAA) units being formed. Order of Battle 1940–41 During The Blitz of 1940–41, 32 AA Bde controlled the following AA units defending the East Midlands: 78 (1st East Anglian) HAA Regiment (part) – formed in 1937 by conversion of 84th (1st East Anglian) Field Brigade, RA; split into detachments during Battle of Britain; concentrated into 40 AA Bde by May 1941 113 HAA Regiment (part) – new unit raised November 1940;113 HAA at RA 39–45 split into detachments during Blitz; concentrated into new 66 AA Bde by May 1941 359, 362, 366, 391 HAA Btys 27 LAA Regiment – raised in Northern Command before September 1939; 'left July 1941 for Eighth Army 107, 113, 149 LAA Btys 38 LAA Regiment (part) – raised in Northern Command before September 1939 64 LAA Regiment (part) – raised November 1940 41st (5th North Staffordshire Regiment) Searchlight Regiment – formed at Stoke-on-Trent in 1936 by conversion of 5th Bn North Staffordshire Regiment from 46 Division 362, 363, 364, 365 S/L Btys 44 Searchlight Regiment – see above 374, 375, 376, 377 S/L Btys 58 (Middlesex) Searchlight Regiment – formed in 1938 as a duplicate of 36 (Middlesex) Searchlight Regiment 344, 425, 426 S/L Btys 511 S/L Bty – attached to 10 AA Division Mid-War The Blitz ended in May 1941, but occasional raids continued. The brigade's order of battle was now predominantly composed of searchlight (S/L) units. AA Command redeployed its S/L units during the summer of 1941 into 'Indicator Belts' of radar-controlled S/L clusters covering approaches to the RAF's Night-fighter sectors, repeated by similar belts covering AA Command's Gun Defence Areas (GDAs). Inside each belt was a 20-mile deep 'Killer Belt' of single S/Ls cooperating with night-fighters patrolling defined 'boxes'. The pattern was designed to ensure that raids penetrating deeply