 During 1939 the 6th Battalion, Essex Regiment duplicated and both the 1/6th and 2/6th battalions became the 64th and 65th Searchlight Regiment respectively, but still remained part of the Essex Regiment.They were transferred to 41st (London) Anti-Aircraft Brigade, 2nd Anti-Aircraft Division, previously the 46th (North Midland) Division.161st Brigade had the following composition during the war