26 lost 8 bombers and 7 fighters for no loss to the RAF, in 'one of the most successful air actions of the war'. The Blitz After the defeat of the Battle of Britain, the Luftwaffe switched to night raids over Britain's cities (The Blitz) during the winter of 1940–41. By 21 August, the Teesside GDA contained 30 HAA guns, and as more LAA units became available they were distributed to defend VPs. AA 'Z' Regiments were also formed, equipped with Z Battery rocket projectiles. The S/L layouts had been based on a spacing of , but due to equipment shortages this had been extended to . The S/L layout was changed in November to clusters of three lights to improve illumination, but this meant that the clusters had to be spaced apart. The cluster system was an attempt to improve the chances of picking up enemy bombers and keeping them illuminated for engagement by AA guns or RAF Night fighters. Eventually, one light in each cluster was to be equipped with searchlight control (SLC or 'Elsie') radar and act as 'master light', but the radar equipment was still in short supply. The number of raiders shot down steadily increased until mid-May 1941, when the Luftwaffe scaled down its attacks. Order of Battle 1940–41 By now AA Command had been greatly expanded and reorganised. The order of battle of 43 AA Bde was now as follows (temporary attachments omitted): 8th (Belfast) HAA Rgt – returned from Dunkirk and re-equipped 21, 22, 23, 414 HAA Btys 59th (Essex Regiment) HAA Rgt – from 6 AA Division Summer 1941 164, 167, 265, 429 HAA Btys 73rd HAA Rgt – returned from Dunkirk and re-equipped; to 12 AA Division May 1941 209, 210, 311 HAA Btys 126th HAA Rgt – new regiment formed July 1941 423, 425, 426 HAA Btys 50th LAA Rgt – new unit raised in July 1940 from a battery of 14th (West Lothian, Royal Scots) LAA Rgt plus recruits 58, 93 LAA Btys 178 LAA Bty – left July 1941 72nd LAA Rgt – new LAA unit raised in January 1941; to 3 AA Division Summer 1941 212, 213, 217 LAA Btys 47th (Durham Light Infantry) S/L Rgt 386, 387, 388, 389 S/L Btys 55th (Durham Light Infantry) S/L Rgt 414, 415, 416, 530 S/L Btys 3 AA 'Z' Rgt – from 3 AA Division Summer 1941 103, 107,