Gas masks were issued to all British civilians at the start of World War Two. There was a very real fear in Britain that Nazi German bombers would drop poison gas bombs. Therefore, all civilians were issued with gas masks. The bombing of Guernica in the Spanish Civil War had shown what could happen when bombers got through. The government had planned for tens of thousands of deaths in London alone. An advisor to the government - Liddell Hart - told the government to expect 250,000 deaths in the first week of the war alone.
At the start of the war some citizens had not been issued with a gas mask. In a government document "If war should come" (issued to people in July 1939), the explanation for this was that district leaders might have decided to keep gas masks in storage until they decided that an emergency situation had developed. However, the public was told to tell their local Air Raid Warden if they had not been issued with a gas mask and neighbours had. It was the responsibility of air raid wardens to ensure that everybody had been issued with a gas mask.
Babies had special gas masks made for them which would only be issued if an emergency situation arose - see above photo. Children were issued with what became known as "Mickey Mouse" gas masks - the nickname was an attempt by the government to make the gas masks seem less scary.
A child's gas mask
The Ministry of Home Safety issued advice on how to put on a gas mask :
Hold your breath
Hold mask in front of face with thumbs inside straps
Thrust chin well forward into mask, pull straps over head as far as they will go
Run finger round face piece taking care head straps are not twisted.
If out of doors people were advised to turn up their jacket collar to stop gas drifting down their necks and to put on gloves or put hands in pockets to stop open skin being hit b gas.
After the Blitz had ended, carrying around a gas mask became less and less important in the mind of the public.
"Gas Masks". HistoryLearningSite.co.uk. 2006. Web.