“Children are taught about sex without being warned that any type of behaviour is wrong, perverted or depraved,” it says. “The truth is that sexual sin has consequences... we reap what we sow.”

The four-page leaflet, Sex Education and the Bible, was written and printed by Dr Edward Williams, a former director of public health in Croydon. It has already been sent to thousands of schools in south London and on the south coast.

The publication was condemned this week as “dangerous”. Marilyn Mason, education officer for the British Humanist Association, said: “I doubt any teachers will be swayed by this, but it is rather disturbing to think it is being sent to every school.”

In the leaflet, it is claimed government guidance on sex and relationship education “does not recognise the concept of sexual immorality, and no form of sexual behaviour is wrong”.

It says: “Children are being persuaded to follow the crowd and have sex.”

The document condemns “explicit” reading materials used in schools, adding:

“Children are coerced into using words and looking at images from which they would normally recoil in shame.” The author also says: “Sex education condones and even encourages homosexual relations.”

Dr Williams, a committed Christian who left Croydon Primary Care Trust in the late 1990s, is also behind such publications as Lessons in Depravity: Education and the Sexual Revolution. The leaflets are produced by his small printing firm, Belmont House, in Sutton, Surrey.

Anna Martinez, co-ordinator for the Sex Education Forum, a national policy advisory group, said: “Sex education is about supporting young people and allowing them to make healthy choices later on in life. The view presented here is an extreme interpretation of what sex education should be about - it is neither balanced nor helpful.”