to leave to return to work or that anti-war sentiment would develop in large congregations of civilians. The government saw the leading role taken by the Communist Party in advocating the building of deep shelters as an attempt to damage civilian morale, especially after the Molotov–Ribbentrop Pact of August 1939. The most important existing communal shelters were the London Underground stations. Although many civilians had used them for shelter during the First World War, the government in 1939 refused to allow the stations to be used as shelters so as not to interfere with commuter and troop travel and the fears that occupants might refuse to leave. Underground officials were ordered to lock station entrances during raids but by the second week of heavy bombing, the government relented and ordered the stations to be opened. Each day orderly lines of people queued until 4:00 pm, when they were allowed to enter the stations. In mid-September 1940, about 150,000 people a night slept in the Underground, although by winter and spring the numbers declined to 100,000 or less. Battle noises were muffled and sleep was easier in the deepest stations, but many people were killed from direct hits on stations. In March 1943, 173 men, women and children were crushed to death at Bethnal Green tube station in a crowd surge after a woman fell down the steps as she entered the station. A single direct hit on a shelter in Stoke Newington on October 1940 killed 160 civilians. Communal shelters never housed more than one seventh of Greater London residents. Peak use of the Underground as shelter was 177,000 on 27 September 1940 and a November 1940 census of London, found that about 4% of residents used the Tube and other large shelters, 9% in public surface shelters and 27% in private home shelters, implying that the remaining 60% of the city stayed at home. The government distributed Anderson shelters until 1941 and that year began distributing the Morrison shelter, which could be used inside homes. Public demand caused the government in October 1940 to build new deep shelters within the Underground to hold 80,000 people but the period of heaviest bombing had passed before they were finished. By the end of 1940 improvements had been made in the Underground and in many other large shelters. Authorities provided stoves and bathrooms and canteen trains provided food. Tickets were issued for