Seventy-one per cent of British people said it was "not at all important" (49%) or "not very important" (22%) for a British prime minister to be a Christian, according to figures collected by Deltapoll last month.
Only 23% thought being a Christian was "quite important" (14%) or "very important" (9%) for a prime minister.
There is no religious qualification for a prime minister, but the UK's head of state, the monarch, holds the title "Defender of the Faith and Supreme Governor of the Church of England". Under current laws, the monarch is required to "join in communion" with the Church of England and promote Anglicanism in Britain.
Catholics are specifically excluded from becoming the monarch.
The UK is also the only democracy to have an explicitly Christian ceremony for its head of state's accession, with the monarch pledging to maintain the "laws of God" during the coronation.
The entanglement of church and state, resulting from the established status of the Church of England, has also caused problems for prime ministers.
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