Cardinal Cormac Murphy-O'Connor has sent a letter to Tony Blair in which he says it would be "unreasonable, unnecessary and unjust discrimination against Catholics" if the Sexual Orientation Regulations will compel the Catholic Church's adoption agencies to place children with gay couples.

In his letter, the head of the Catholic Church in England and Wales reaffirmed the wish of the Church to work with the Government but said that he would have a "serious difficulty" with the Sexual Orientation Regulations if "they required our adoption agencies to consider homosexual couples as potential adoptive parents".

Cardinal Murphy-O'Connor stressed that the Church did not support discrimination or abuse directed against homosexuals.

"The Catholic Church utterly condemns all forms of unjust discrimination, violence, harassment or abuse directed against people who are homosexual. Indeed the Church teaches that they must be accepted with respect, compassion and sensitivity," he said.

Cardinal Murphy-O'Connor also welcomed aspects of the legislation which would safeguard against such discrimination.

"We, therefore, recognise many elements of recent legislation - including much in the Northern Ireland Regulations - that takes steps to ensure that no such discrimination takes place."

Cardinal Murphy-O'Connor went on to outline the Church's opposition to the regulations, however, saying that "to oblige our agencies in law to consider adoption applications from homosexual couples as potential adoptive parents would require them to act against the principles of Catholic teaching".

In the letter, Cardinal Murphy-O'Connor said, "We place significant emphasis on marriage, as it is from the personal union of a man and a woman that new life is born and it is within the loving context of such a relationship that a child can be welcomed and nurtured.

"Marital love involves an essential complementarity of male and female," said Cardinal Murphy-O'Connor, although he added that the Church's adoption agencies were willing to consider placing children with a single adoptive parent.

The letter continued: "However, Catholic teaching about the foundations of family life, a teaching shared not only by other Christian churches but also other faiths, means that Catholic adoption agencies would not be able to recruit and consider homosexual couples as potential adoptive parents.

"We believe it would be unreasonable, unnecessary and unjust discrimination against Catholics for the Government to insist that if they wish to continue to work with local authorities, Catholic adoption agencies must act against the teaching of the Church and their own consciences by being obliged in law to provide such a service."

Applications to the Catholic adoption agencies from homosexual couples are currently referred to other agencies with a pro-gay adoption policy.

"This 'sign-posting' responsibility is taken very seriously by all Catholic adoption agencies," Cardinal Murphy-O'Connor concluded.