<P> Finally, Göring stopped the attacks on the radar chain . These were seen as unsuccessful, and neither the Reichsmarschall nor his subordinates realised how vital the Chain Home stations were to the defence systems . It was known that radar provided some early warning of raids, but the belief among German fighter pilots was that anything bringing up the "Tommies" to fight was to be encouraged . </P> <P> On the afternoon of 15 August, Hauptmann Walter Rubensdörffer leading Erprobungsgruppe 210 mistakenly bombed Croydon airfield (on the outskirts of London) instead of the intended target, RAF Kenley . </P> <P> German intelligence reports made the Luftwaffe optimistic that the RAF, thought to be dependent on local air control, was struggling with supply problems and pilot losses . After a major raid attacking Biggin Hill on 18 August, Luftwaffe aircrew said they had been unopposed, the airfield was "completely destroyed", and asked "Is England already finished?" In accordance with the strategy agreed on 6 August, defeat of the RAF was to be followed by bombing military and economic targets, systematically extending up to the Midlands . </P> <P> Göring ordered attacks on aircraft factories on 19 August 1940 . Sixty raids on the night of 19 / 20 August targeted the aircraft industry and harbours, and bombs fell on suburban areas around London: Croydon, Wimbledon and the Maldens . Night raids were made on 21 / 22 August on Aberdeen, Bristol and South Wales . That morning, bombs were dropped on Harrow and Wealdstone, on the outskirts of London . Overnight on 22 / 23 August, the output of an aircraft factory at Filton near Bristol was drastically affected by a raid in which Ju88 bombers released over 16 tons of high explosive bombs . On the night of 23 / 24 August over 200 bombers attacked the Fort Dunlop tyre factory in Birmingham, with a significant effect on production . A sustained bombing campaign began on 24 August with the largest raid so far, killing 100 in Portsmouth, and that night, several areas of London were bombed; the East End was set ablaze and bombs landed on central London . Some historians believe that these bombs were dropped accidentally by a group of Heinkel He 111s which had failed to find their target; this account has been contested . </P>

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