In Britain, the Second World War began on a Sunday. On 3 September 1939 Neville Chamberlain announced the government's declaration of war against Nazi Germany in a BBC radio broadcast to the nation at 11.15 a.m., while many people were attending divine worship and large numbers of children were at Sunday school. In numerous cathedrals, churches and chapels, the news was reported from pulpits; in others, radios had been installed so that the prime minister's words could be heard directly by their congregations. The war began amid prayers. Chamberlain's broadcast contained a religious appeal: ‘May God bless you all. May He defend the right.’ King George VI, broadcasting in the evening, called on the peoples of Britain and its empire to ‘reverently commit our cause to God. If one and all we keep resolutely faithful to it, ready for whatever service or sacrifice it may demand, then, with God's help, we shall prevail.’ The king's words had been composed by the archbishop of Canterbury, Cosmo Lang, who delivered a broadcast address of his own two hours later. On the following day, Lang asked Chamberlain for government support in arranging a national day of prayer. With the king's public approval, this was observed a main British churches, through broadcast services on all BBC channels, and in many churches in the overseas dominions and colonies, huge numbers of people joined in special appeals for God's assistance in the war.

The use of religious language by British leaders, the close co-operation between the state, the churches and the BBC, and the organization of special acts of worship all increased as the war proceeded. Together, these amounted to a ‘spiritual mobilization’ of the nation and empire, and a call for spiritual solidarity from the governments and peoples of other nations. Wartime recruitment of religion and the churches was hardly new. During the wars of previous centuries, sovereigns, governments and the established churches had claimed God's special favour for the kingdom and its allies, ordered special prayers and religious fast and thanksgiving days, and aimed to convince their own people and other nations of the righteousness of their cause, the spiritual resources for endurance and hope, and a providential assurance of eventual victory and a better future. Yet the extent and effects of the state's mobilization of religion and the churches during the Second World War await systematic investigation.