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 will also highlight the issue in a speech at the Vatican later on Tuesday.
David Cameron has said that the UK is a Christian country "and we should not be afraid to say so".
In a speech in Oxford on the 400th anniversary of the King James Bible, the prime minister called for a revival of traditional Christian values to counter Britain's "moral collapse".
The head of the UK border force has been suspended by the Home Office following allegations staff were told to scale down some identity checks.
The official who has been suspended is Brodie Clark, who also sits on the board of the UK Border Agency (UKBA).
The Home Office says it is investigating the allegations and has made no further comment.
Staff working for the UK border force, which is part of the UKBA, are responsible for checking passports.
They also carry out immigration raids
Noor TV has been fined a hefty £75,000 after it broadcast a show allowing viewers to donate money to the channel in return for prayers for themselves or for their relatives.
A complainant was concerned that a programme exploited the audience by encouraging viewers to donate money to Noor TV in return for the channel arranging special prayers inside Prophet Muhammad's mosque in Medina. The complainant noted that many of the callers who donated money asked for prayers to be made to assist with their medical, financial and personal problems.
Noor Tv fined
Killed for a free breakfast
Joshua Davies lured 15-year-old Rebecca Aylward into woodland near Bridgend in South Wales and tried to strangle her.
When that failed, he smashed her skull with a rock the size of a rugby ball.
Davies, 16, left Rebecca face down in the pouring rain in the new clothes she had bought for their meeting.
He later returned to the wood with a friend to show him the body. At his trial, Davies tried to blame the friend for the killing
A 29-year-old man has become the youngest grandfather in Britain after his 14-year-old daughter gave birth, a media report said.
Shem Davies - of Bridgend, Wales - was also 14 when he became a father for the first time, The Sun reported.
His schoolgirl daughter Tia now has had a girl before her 15th birthday, it said.
Davies - who split with Tia's mother Kelly three months after she was born - said he was 'absolutely delighted' at the news.
Davies was 'shocked' when his daughter told him she was pregnant by her 15-year-old boyfriend.
He also has a nine-month-old son with new girlfriend Robyn Thomas.
