"Never in the field of human conflict was so much owed by so many to so few..." (Churchill) This part of the speech refers to the ongoing efforts of the Royal Air Force pilots who were at the time fighting the Battle of Britain, the pivotal air battle with the German Luftwaffe with Britain expecting a German invasion.
An official photo describing the kit of a British infantryman in 1939. Note that the gas mask ('respirator') and anti-chemical warfare cape are parts of the outfit, remnants of WW1 memories. In actual combat, and marching with full kit, the British infantryman would carry a pack known as a "valise" that contained more clothing and personal items. Officers wore the exact same uniform save for markings of their rank.