Light Infantry HQ, 411th–413th Searchlight Batteries at Stockton-on-Tees 2/5th Battalion, Durham Light Infantry (55th Searchlight Regiment) – duplicate unit formed in April 1939 HQ, 414th–416th Searchlight Batteries at West Hartlepool 43rd Anti-Aircraft Brigade Company, Royal Army Service Corps Phoney War Equipment was critically short at the outbreak of war. In August 1939, 7 AA Division only had 14 3-inch or 3.7-inch Heavy AA guns deployed on Teesside. Luckily, the months of the Phoney War that followed mobilisation allowed AA Command to address its equipment shortages and a Gun Defence Area (GDA) was established around Teesside including Middlesbrough and Billingham. Vital Points (VPs) such as RAF Fighter Command airfields and factories began to receive a few Bofors LAA guns. 85th AA Regiment left the brigade in November 1939 to mobilise for overseas service; in April 1940 it joined the British Expeditionary Force in France. Later, 54th S/L Regiment transferred to 31st (North Midland) Anti-Aircraft Brigade covering West Yorkshire. Battle of Britain After the Fall of France and the BEF's evacuation from Dunkirk, returning AA units were re-equipped and re-integrated into AA Command as quickly as possible. By the summer of 1940, all TA searchlight regiments had been transferred to the Royal Artillery (RA), and AA regiments had been redesignated Heavy Anti-Aircraft (HAA) to distinguish them from the new Light Anti-Aircraft (LAA) regiments being formed. Teesside and Wearside were important strategic targets because of their concentrations of heavy industry and ports. During the early part of the Battle of Britain, German day and night air raids and mine laying began along the East Coast of England, intensifying through June 1940. Thereafter the Luftwaffe concentrated on Royal Air Force sites in the South of England, with occasional raids on the North East, such as the period 12–15 August. On 15 August, in the belief that the defences of NE England had been denuded, Luftflotte 5 attacked across the North Sea from Norway. Some 65 Heinkel He 111 bombers of Kampfgeschwader 26 escorted by 35 Messerschmitt Bf 110 Zerstörer fighters of Zerstörergeschwader 76 were picked up on radar and ambushed by fighters of No. 13 Group RAF before they reached the coast. Those bombers that succeeded in breaking through then split into two groups, one being engaged by the guns of the Tyne GDA the other by the Tees GDA. Bombs were widely scattered and only at Sunderland was any major damage inflicted. KG