London's Most Realistic Air Raids Precautions Test - A newsboy wearing gas mas selling papers to say war is Deolared, - one of the many realistic touches. One of the most realistic air raid precaution demonstration so far staged was produced by Kensington borough council last evening. For the purpose a large piece of waste ground opposite Olympia in Kensington high street was converted into an open-air theatre with 4,000 free seats for the public. May 27, 1938. (Photo by Keystone).;London's Most