The Vatican has backed a Roman Catholic bishop who has told Catholic schools in his diocese to reject "safe sex" education because it is "dangerous and immoral".

The Bishop of Lancaster, the Rt Rev Nutter Patrick O'Donoghue, said in a document calling for traditional moral teaching that "so-called" safe sex was based on the deluded theory that the condom can provide adequate protection against Aids.

Archbishop Mauro Piacenza, the secretary of the Congregation for the Clergy, said in a letter that the document was fully in line with Vatican teaching.

However, Barry Sheerman, the Labour MP who chairs the influential Commons committee on schools, said he feared that it presaged a new fundamentalism among some Catholic bishops, encouraged by the Vatican.

A Roman Catholic bishop has likened books which criticise the teachings of the Church to works that deny the Holocaust took place.

The Rt Rev Nutter Patrick O'Donoghue, Bishop of Lancaster, told MPs that books critical of the Catholic faith should be banned from school libraries.

Asked if that applied to works by authors such as Karl Marx and Albert Camus, he told the Commons Children, Schools and Families Committee: Suppose you went into a school and found in the library material that said the Holocaust never took place?

Fiona McTaggart, the Labour MP for Slough, said she was extremely concerned that Catholic sixth-formers would be denied access to great works of fiction as well as non-fiction if the bishop's ban were implemented. I would not expect a school to promote material that was lies but I also would also expect children to encounter a wide range of material even if they then need to be given the tools to criticise them, she said.

But Bishop O'Donoghue defended his stance. I think there has to be a vetting of material given the age range of children in schools. There is certain material that you do not put in front of them.

The bishop's summons to appear before the committee followed a document he produced last year which angered some MPs because of its strict line on sexual morality. In Fit for Mission?, Bishop O'Donoghue wrote: The secular view on sex outside marriage, artificial contraception, sexually transmitted disease, including HIV and Aids, and abortion, may not be presented as neutral information. "So-called" safe sex was based on the deluded theory that the condom can provide adequate protection against Aids. Schools and colleges must not support charities or groups that promote or fund anti-life policies, such as Red Nose Day and Amnesty International, which now advocates abortion.