The second most senior cleric in the Church of England, Archbishop of York John Sentamu, on Saturday condemned the British government's plans to introduce same-sex civil marriages.

"Marriage is a relationship between a man and a woman," the Ugandan-born archbishop told the Daily Telegraph newspaper, adding that only "dictators" tried to redefine things that were so established in tradition and history.

Prime Minister David Cameron's government is due to launch a consultation on same-sex civil marriages in March, more than six years after homosexual civil partnerships were introduced in December 2005.

But 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 that the Church, whose job is to worship God [will be] an arm of the armed forces. They must take arms and fight. You?re completely changing tradition."

Sentamu warned that if new legislation was introduced to allow same-sex marriage, there would be a rebellion not just from bishops in the unelected upper House of Lords, but from all parties and in the elected House of Commons.

"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," he said.

"That does not mean you diminish, condemn, criticise, patronise any same-sex relationships because that is not what the debate is about."