David Cameron's remarks that the UK is a "Christian country" were criticised by a group of public figures. What are the arguments for and against the prime minister's claim?
Writing for the Church Times, the prime minister said British people should "be more confident about our status as a Christian country".
In response, 50 prominent individuals including authors, broadcasters, comedians and scientists added their names to a letter to the Daily Telegraph which argued the UK was a largely "non-religious society". Two senior Conservative ministers have backed the prime minister, arguing that those who deny the UK is a Christian country are "deluding themselves".
So what are the main arguments?
For: The census
In the 2011 census 59% of residents of England and Wales described themselves as Christian when asked "What is your religion?" This was down from 72% in 2001. In Scotland, the figure was 54%, down from 65%. In Northern Ireland 83% said they belonged to a Christian denomination.
Although the total number of Britons who described themselves as Christian had fallen by more than four million since 2001, the fact it constitutes a majority is "really, really significant", says Christina Rees, a member of the general synod, the highest governing body of the Church of England.
"That's a strong number and the census is one of the more reliable ways of getting information in this country," Rees adds. "You could be picky and say they don't all go to church but they have chosen to identify as Christian."
Against: Church attendance
Secularists say it's entirely reasonable to be picky on this subject. According to the Church of England's own figures, 800,000 people would have attended a service on a typical Sunday in 2012. This is approximately half the number that attended in 1968.
Andrew Copson, chief executive of the British Humanist Association, says the census question is "flawed" because it assumes the respondent has a religion in the first place. The 2013 British Social Attitudes Survey reported that 48% of respondents claimed they did not belong to a religion. The proportion of people who described themselves as belonging to the Church of England was just 20%, down from 40% in 1983.
"'Any politician or government that tried to make Christianity and Christian beliefs the foundation of British values or social morality would be building on seriously unstable foundations," says Copson.
For: Established church
England has an established Church. Its bishops sit in the House of Lords. The Queen is both head of state and also supreme governor of the Church of England. One of the monarch's titles is Defender of the Faith.
Because of this, Work and Pensions Secretary Iain Duncan Smith has told the Daily Telegraph that claims the UK was not a Christian country ignored "both historical and constitutional reality". The legal system was founded on "the Christian principles of justice and fairness", says Rees.
Harry Cole - a "lapsed agnostic" who is open to disestablishing the church - writes in the Spectator that it is impossible to deny the UK is a Christian country without attempting to "rewrite history and ignore our heritage".
Against: Waning influence
The laws relating to abortion, same-sex marriage, the teaching of homosexuality, adoption and other issues have changed in spite of vocal opposition from religious groups. For secularists, this is evidence that the Church's prestige and importance is no longer what it once was.
In a 2006 Ipsos MORI poll, "religious groups and leaders" topped the list of domestic groups that people said had too much influence over ministers. A 2013 Lancaster University study of British Catholics suggested they were wildly at odds with their spiritual leaders on matters of personal morality. According to the survey, only 9% would feel guilty using contraception and just 19% would support a ban on abortion. More favoured allowing same-sex marriage than were opposed.
"The law that Christianity imposed on us is gradually being eroded and reformed," says Terry Sanderson, president of the National Secular Society (NSS). "It's true that Christianity informed our laws but they are rapidly changing because we are being secularised."
For: Cultural Christianity
Even Richard Dawkins, figurehead for many atheists, has described himself as a "cultural Christian" who liked "singing carols along with everybody else". While Dawkins himself rejects the teaching of the church, Rees says the widespread attachment to the Christian rituals, symbolism and institutions is further evidence that people still regard the church as occupying a central role in civic life.
"The most significant events in people's lives - getting married, having your babies baptised, saying goodbye to a loved one - these tend to happen in a church," says Rees.
Attorney General Dominic Grieve, a patron of the Conservative Christian Fellowship, said that atheism had not made "much progress" in the UK. "Many of the underlying ethics of society are Christian-based and the result of 1,500 years of Christian input into our national life," he said. In 2011 there were 51,880 weddings, 139,751 baptisms and 162,526 funerals conducted by Church of England clergy. Some 68% of 2010's marriages were civil ceremonies according to ONS. There were 729,674 live births and around 500,000 deaths registered in England and Wales in 2012.
The prominent role of the church in the country's education system may have much to do with this. In 2011, about one third of England's 20,000 state-funded schools were faith schools, of which 68% were affiliated to the Church of England schools and 30% were Roman Catholic.
Against: Non-Christian influences
In their letter to the Daily Telegraph, pro-secularist public figures argued that "Britain has been shaped for the better by many pre-Christian, non-Christian, and post-Christian forces".
While praising the contributions of Christians to public life they said it was wrong to "exceptionalise" them over and above those of different faiths and of none.
Britons who are agnostic, atheist, Hindu, Jewish, Muslim, Sikh and who share other non-Christian belief system have all made a positive contribution to British culture, Sanderson says.
For: The calendar
A glance at the way national holidays are structured - not to mention the working week - demonstrates the continued influence of Christianity, says Rees.
"The major holidays around Christmas and Easter are there for the Christian festivals and events," she says. Despite occasional warnings about a "war on Christmas", both festivals are widely celebrated by Christians and non-Christians alike.
Although Sunday trading laws have been relaxed, "there's still an awareness of trying to keep one day that's for something more than earning money and the daily grind".
Against: Rise of other religions and the non-religious
The 2011 census suggested there were 14.1 million people of no religion compared with 7.7 million a decade previously. This represented a rise from 15% to 25% of the population. It also showed an increase in the number of Muslims, with the proportion of the population in 2011 standing at 4.8%, or 2.7 million, up 2% or 1.5 million in 2001.
The Buddhist, Hindu, Jewish and Sikh faiths all registered increases. There were 817,000 Hindus in 2011, a rise of 264,000 since 2001. The Jewish faith also rose by 3,000 over the last decade from 260,000 to 263,000.
When the census was released, Nick Spencer, research director at think-tank Theos, said the UK had "a plural religious landscape". Groups like the NSS say it is unfair to give one faith group advantages in this context.