Former attorney general Dominic Grieve tells The Telegraph that British Christians are being "forced to hide belief".
He told the newspaper that an "aggressive form of secularism" was present in places of employment and in public bodies, and that attempts to push faith out of the public space were visible at local government level.
Mr Grieve, a member of the Church of England, spoke of a "sanitisation" that will "lead to people of faith excluding themselves from the public space and being excluded".
He alluded to instances of believers being disciplined or sacked because they expressed their faith at work.
He told The Telegraph: "I worry that there are attempts to push faith out of the public space. Clearly it happens at a level of local power.
"You can watch institutions or organisations do it or watch it happen at a local government level. In my view it's very undesirable."
He was critical of the "we don't do God" attitude of the previous Labour Government, saying that "politicians should express their faith".
"I have never adhered to the Blair view that we don't do God, indeed I'm not sure that Blair does. I think that people with faith have an entitlement to explain where that places them in approaching problems."
He said it was "very important" to recognise people's right to manifest their faith and express it, and that the ongoing murder of Christians in Iraq made this "more important than ever".
And while he admitted being a Christian "doesn't mean we have the monopoly of wisdom", the faith had played "an enormous role in shaping this country" and is "underrated".
This was, he contended, "partly because in the past it has failed to express itself as clearly as it might."