The Archbishop of York appears to have claimed the Church of England must give its permission to the legal extension of equal marriage rights to gay couples even in a civil setting.

Speaking on the Andrew Marr Show this weekend, he said the government “have got a problem because the definition of marriage is in the 1662 Prayer Book and Article 30 of the Church of England, which are both Acts of Parliament.”

He told the BBC: “I happen to believe that to change the law in the end would be forcing an unjustified change.”

Adam Wagner, barrister and founding editor of the UK Human Rights Blog told the Independent he doubted the Archbishop of York’s understanding of the law.

He said: “I can’t see why Parliament would need anyone’s approval to change the definition of marriage. Parliament is sovereign, it can legislate what it likes.”

The government’s consultation on how to introduce equal civil marriage rights is due to begin this week. Ministers have frequently assured churches that they would not be compelled to perform weddings ceremonies for gay couples if they choose not to.

The Archbishop last weighed into the debate on equal marriage in January when he said it was 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”.

Comparing the passage of equal marriage rights laws to the actions of a dictator drew protests outside his seat, York Minster.

He had told the Daily Telegraph: “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.”

The consultation will not cover religious marriages between gays, only civil unions, but it has prompted increasing criticism from senior figures in the Church of England and the Roman Catholic Church over the past weeks.