London, England - A British Muslim leader has told the BBC he believes homosexuality is "not acceptable" and denounced new same-sex civil partnerships as "harmful".
Head of the Muslim Council of Britain Sir Iqbal Sacranie said introducing the partnerships did "not augur well" for building the foundations of society.
Nevertheless, he told BBC Radio 4's PM programme, everyone should be tolerant.
Peter Tatchell of gay rights group OutRage! said: "It is tragic for one minority to attack another minority."
Sir Iqbal said of civil partnerships: "This is harmful.
"It does not augur well in building the very foundations of society - stability, family relationships. And it is something we would certainly not, in any form, encourage the community to be involved in."
He said he was guided by the teachings of the Muslim faith, adding that other religions such as Christianity and Judaism held the same stance.
Asked if he believed homosexuality was harmful to society, he said: "Certainly it is a practice that in terms of health, in terms of the moral issues that comes along in a society - it is. It is not acceptable."
"Each of our faiths tells us that it is harmful and I think, if you look into the scientific evidence that has been available in terms of the forms of various other illnesses and diseases that are there, surely it points out that where homosexuality is practised there is a greater concern in that area."
He said everyone in society should be tolerant, and if they are not happy then engage in the democratic processes to give their views.
"We may not be happy with the views being expressed by others. But the difficulty comes in that at the end of the day we are human beings."
He said both the opponents and supporters of civil partnerships had the right to speak out.
Mr Tatchell, the founder of OutRage!, added: "Both the Muslim and gay communities suffer prejudice and discrimination. We should stand together to fight Islamophobia and homophobia."