Britain is under threat from a rising tide of "militant secularisation", a cabinet minister has warned.
Religion is being "sidelined, marginalised and downgraded in the public sphere" , Conservative co-chairwoman Baroness Warsi wrote in an article for the Daily Telegraph.
The Muslim peer said Europe needed to become "more confident and more comfortable in its Christianity".
She also highlighted the issue in a speech at the Vatican on Tuesday.
She wrote in the Telegraph that "to create a more just society, people need to feel stronger in their religious identities and more confident in their creeds".
"In practice this means individuals not diluting their faiths and nations not denying their religious heritages."
Baroness Warsi, who is Britain's first female Muslim cabinet minister, went on to write: "You cannot and should not extract these Christian foundations from the evolution of our nations any more than you can or should erase the spires from our landscapes."
She wrote that examples of a "militant secularisation" taking hold of society could be seen in a number of things - "when signs of religion cannot be displayed or worn in government buildings; when states won't fund faith schools; and where religion is sidelined, marginalised and downgraded in the public sphere".
She also compared the intolerance of religion with totalitarian regimes, which she said were "denying people the right to a religious identity because they were frightened of the concept of multiple identities".
Her comments come days after the High Court ruled that a Devon town council had acted unlawfully by allowing prayers to be said at meetings.
'Outdated and divisive'
On Baroness Warsi's article and speech, BBC political correspondent Louise Stewart said it was not the first time a senior Conservative had called for a revival of traditional Christian values.
"Last December, Prime Minister David Cameron said the UK was a Christian country and 'should not be afraid to say so'," she said.
The British Humanist Association (BHA) described Baroness Warsi's comments as "outdated, unwarranted and divisive".
"In an increasingly non-religious and, at the same time, diverse society, we need policies that will emphasise what we have in common as citizens rather than what divides us," said BHA chief executive Andrew Copson.
Baroness Warsi's two-day delegation of seven British ministers to the Holy See will include an audience with Pope Benedict XVI, who visited the UK in 2010.
It is understood it is the first time a serving minister of a foreign government has given an address to the staff and students of the Pontifical Ecclesiastical Academy, the British Embassy to the Holy See said.
This visit marks the 30th anniversary of the re-establishment of full diplomatic ties between Britain and the Vatican.
'No logical basis'
Meanwhile, new research suggests Britons who declare themselves Christian display low levels of belief and practice.
Almost three quarters of the 1,136 people polled by Ipsos Mori agreed that religion should not influence public policy, and 92% agreed the law should apply to everyone equally, regardless of their personal beliefs.
It also found that 61% of Christians agreed homosexuals should have the same legal rights in all aspects of their lives as heterosexuals.
And a further 62% were in favour of a woman's right to have an abortion within the legal time limit.
The survey was conducted for the Richard Dawkins Foundation for Reason and Science (UK), which describes itself as promoting "scientific education, rationalism and humanism".
Speaking on Baroness Warsi's comments, Mr Dawkins, former professor for the public understanding of science at Oxford University, told the BBC News Channel: "She is obviously a person who really wants to push religion.
"She is not Christian herself but nevertheless she sees religion as a good thing - it doesn't matter what religion as long as there's some religion and that's better than no religion.
"There is absolutely no logical basis for that."