Churchill and the RAF weren’t available to head off this German invasion. The proliferation of German discount grocers Aldi and Lidl in the U.K. over the past decade carved out a new battlefield for Tesco, Sainsbury’s, Asda, and Morrisons, and they are still mired in the mud. Second-quarter results released by market researcher Kantar showed the Germans growing 19% over last year, while the British Big Four edged up less than 2%.