ille ▁after ▁abandon ing ▁its ▁guns ▁in ▁the ▁w ake ▁of ▁the ▁Fall ▁of ▁France . ▁▁ 2 8 ▁A AB ▁was ▁responsible ▁for ▁the ▁def ences ▁on ▁the ▁south ▁side ▁of ▁the ▁Th ames ▁Est u ary ▁( Th ames ▁South ) ▁including ▁the ▁Royal ▁Naval ▁D ock yard ▁at ▁Ch ath am , ▁as ▁well ▁as ▁the ▁Port ▁of ▁D over . ▁By ▁ 1 1 ▁July ▁ 1 9 4 0 , ▁the ▁Th ames ▁South ▁AA ▁layout ▁operated ▁by ▁ 2 8 ▁AA ▁B de ▁had ▁a ▁total ▁of ▁ 7 0 ▁H AA ▁guns ▁( 3 . 7 - inch ▁and ▁ 4 . 5 - inch ). ▁ ▁Battle ▁of ▁Britain ▁ ▁The ▁Luft wa ffe ▁began ▁its ▁ 1 9 4 0 ▁bomb ing ▁off ensive ▁against ▁the ▁British ▁main land ▁with ▁small - scale ▁ra ids ▁on ▁coast al ▁targets . ▁In ▁July ▁ 1 9 4 0 ▁it ▁began ▁heavy ▁day light ▁ra ids ▁against ▁south ▁coast ▁ports ▁and ▁sh ipping ; ▁the ▁guns ▁at ▁D over ▁were ▁in ▁action ▁virt ually ▁every ▁day . ▁Lieutenant - Col onel ▁N . V . ▁Sad ler ▁of ▁ 7 5 th ▁H AA ▁Regiment ▁developed ▁an ▁effective ▁system ▁of ▁H AA ▁bar rages ▁over ▁individual ▁points ▁in ▁D over ▁Har bour ▁and ▁the ▁sh ipping ▁channels , ▁under p inned ▁by ▁light ▁anti - air craft ▁( LA A ) ▁fire . ▁In ▁one ▁day ▁the ▁regiment ▁claimed ▁to ▁have ▁shot ▁down ▁ 1 0