David Cameron would be like a "dictator" if he allowed same-sex marriage, according to the Archbishop of York.
Dr John Sentamu, the second most senior cleric in the Church of England, said that politicians should not overrule the bible and allow homosexual couples to get married, insisting that the institution must remain between a man and a woman.
The incendiary comments by a senior member of the Church of England are likely to infuriate human rights campaign groups, with campaigner Peter Tatchell calling Archbishop Sentamu "a religious authoritarian"
In an interview in the Daily Telegraph, Sentamu said: "I don't think it is the role of the state to define what marriage is. It is set in tradition and history and you can't just (change it) overnight, no matter how powerful you are.
"We've seen dictators do it in different contexts and I don't want to redefine very clear social structures that have been in existence for a long time and then overnight the state believes it could go in a particular way.
"It's almost like somebody telling you overnight that the Church, whose job is to worship God (that it will be) an arm of the Armed Forces. They must take arms and fight. You're completely changing tradition."
Reported by the Press Association, Sentamu pointed out that the bishops in the House of Lords did not try to stop Labour introducing civil partnerships in 2004, which gave same-sex couples much improved legal rights.
The Archbishops also reiterated has support for the move to allow civil partnership ceremonies in places of worship, subject to the voluntary agreement of the denomination's governing body.
However, the government is likely to face stiff opposition from the Lords and, according to Sentamu, the Commons, should they try and introduce legislation on gay civil marriage.
"The rebellion is going to come not only from the bishops. You're going to get it from across the benches and in the Commons," he said.
"If you genuinely would like the registration of civil partnerships to happen in a more general way, most people will say they can see the drift. But if you begin to call those marriage, you're trying to change the English language.
"That does not mean you diminish, condemn, criticise, patronise any same-sex relationships because that is not what the debate is about.
"The Church has always stood out - Jesus actually was the odd man out. I'd rather stick with Jesus than be popular because it looks odd."
Sentamu has previously expressed concern over the "gay marriage" of homosexual clergy after two reverends exchanged rings and vows at a service held in St Bartholomew the Great Church in the City of London in 2008
In a joint statement with the Archbishop of Canterbury Dr Rowan Williams, he said: "Those clergy who disagree with the Church's teaching are at liberty to seek to persuade others within the Church of the reasons why they believe, in the light of Scripture, tradition and reason that it should be changed. "But they are not at liberty simply to disregard it."
In reaction the Sentamu's statement, Tatchell, co-ordinator of the Equal Love campaign, said: "Archbishop Sentamu is a religious authoritarian who wants to impose his personal opposition to same-sex marriage on the rest of society.
"It is not a Christian value to demand legal discrimination against gay couples and to treat them as inferior, second-class citizens - with fewer rights than everyone else.
"The Government is proposing to legalise same-sex civil marriages in register offices. This will not affect churches.
"The Archbishop has no valid grounds for objecting to civil legislation that will ensure marriage equality for all couples."