Employers have been told that they should review their current policies and rules to ensure that they do not "directly or indirectly discriminate against staff holding particular beliefs".

In the 12 months to April 2008, 600 people took their employers to a tribunal on the grounds of religious discrimination – up from 486 two years previously.

The new guidelines come from the Chartered Management Institute (CMI), and come on the back of a number of high profile cases of Christians facing legal action or investigations by their employers.

Caroline Petrie, an NHS nurse, was suspended for offering to pray for a patient and later reinstated. In another case Jennie Cain, a school secretary, may be sacked after her daughter spoke about Christianity at school.

The new guidelines say that managers are responsible for educating themselves about religious discrimination law and for making “reasonable changes” to company procedures.

Andrea Williams, of the Christian Legal Centre, welcomed the guidelines but also called for a debate on the issue of religious liberties.

She said, “Recent cases of manifest injustice and discrimination against Christians have shown that sometimes in today’s Britain a well-meaning desire for equality and inclusion can have the exact opposite effect, by discriminating against those who hold to the Christian faith,” reports the Telegraph.

Williams continued, “These are key issues going to the heart of our liberties and rights and we must have a thorough and genuine debate around them."

Jo Causon of the CMI said, "There have been several well publicised incidents recently which have bought issues of belief in the workplace to greater prominence.

"Employers need to know the law and work within it, but they also need to manage relationships to ensure organisations and their employees can thrive. It is unacceptable to discriminate on the basis of religion, belief or any other form of discrimination."