Religious groups have backed Prime Minister David Cameron's assertion Britain is "a Christian country".
Hindu Council UK said it was "very comfortable" with the description. The Muslim Council of Britain said the UK was a largely Christian country.
He said the UK must be "more confident" about its Christianity, a view Downing Street says he has stated before.
Writing for the Church Times earlier this month, Mr Cameron said: "Crucially, the Christian values of responsibility, hard work, charity, compassion, humility, and love are shared by people of every faith and none - and we should be confident in standing up to defend them."
This did not mean "doing down" other religions, he said.
The prime minister also spoke of his faith in his Easter message, saying he found "peace" in Christianity.
Public figures, including authors Sir Terry Pratchett and Philip Pullman - in an open letter published in Monday's Daily Telegraph - said: "We object to his characterisation of Britain as a 'Christian country' and the negative consequences for politics and society that this engenders.
"Apart from in the narrow constitutional sense that we continue to have an established Church, Britain is not a 'Christian country'.
"Constantly to claim otherwise fosters alienation and division in our society."
Other signatories - led by British Humanist Association president Prof Jim Al-Khalili, president of the British Humanist Association - include performer Tim Minchin, journalist Polly Toynbee and philosopher AC Grayling.
Andrew Copson, chief executive of the British Humanist Association, told the BBC: "I think it's a bit off to try and say we're a Christian country which is hospitable to others, instead of to try and reflect the truth, which is that we're a country with a great plurality of identities."
Muslim Council of Britain secretary general Farooq Murad said nobody could deny the UK remained a largely Christian country with "deep historical and structural links" to Christianity.
"A sense of the sacred is to be cherished", he said, adding the UK would be stronger by "recognising and celebrating" people of multiple faiths and of no faith "living in harmony".
Anil Bhanot, managing director of Hindu Council UK, said he was "very comfortable" with the UK being described as a Christian country, adding many Hindu people celebrated Christmas and Easter.
"People can secularise those traditions but it doesn't take away from the fact that the country was based in Christian traditions," he said.
Christina Rees, a member of the General Synod, the highest governing body of the Church of England, said she was glad Mr Cameron had the "confidence" to talk about his faith.
The UK had "historically and culturally" been a Christian country for "many hundreds of years", she added.
Human rights campaigner Peter Tatchell told BBC Radio 4's Today programme it was "not factually accurate" to call Britain a Christian country.
He said a YouGov poll found 65% of people questioned described themselves as "not religious", while 29% said they were. He said those people would have come from a range of faiths - not just Christianity.
His claims come after figures released by the ONS following the 2011 census found that, despite a drop of four million in the number of people who said they were Christians in England and Wales from 2001, 59% of residents still described themselves as Christian.
A Downing Street spokeswoman made reference to a 2011 speech in which Mr Cameron said the UK was a Christian country "and we should not be afraid to say so".
"He has said on many occasions that he is incredibly proud that Britain is home to many different faith communities, who do so much to make the UK a stronger country," she added.