They are known as "The special British civilian respirator"
Great Britain was the only country during World War II to fully equip every civilian man, woman and child with a respirator free of charge. It was realised early on that those who were bedridden, suffering from respiratory difficulties, heart problems or who had undergone tracheotomy, were unable to use the standard respirator. However, research led to three special respirators being made available to cope with most medical conditions. The civilian respirators were developed and continued to be produced well into the 70's. They are stored in their millions undergound along with tons and tons of emergency rations, stores, water, etc etc etc.
Right, enough about gas masks...