The Archbishop of Canterbury, Dr Rowan Williams, has called for new laws to protect religious sensibilities that would punish “thoughtless and cruel” styles of speaking.

Dr Williams, who has seen his own Anglican Communion riven by fierce invective over homosexuality, said the current blasphemy law was “unworkable” and he had no objection to its repeal.

But whatever replaces it should “send a signal” about what was acceptable.

This should be done by “stigmatising and punishing extreme behaviours” that have the effect of silencing argument.

The Archbishop, delivering the James Callaghan Memorial Lecture in London this afternoon, said it should not just be a few forms of extreme behaviour that were deemed unacceptable, leaving everything else as fair game.

“The legal provision should keep before our eyes the general risks of debasing public controversy by thoughtless and, even if unintentionally, cruel styles of speaking and acting,” he said.

The last conviction under Britain’s blasphemy law was in 1979. The Government recently indicated it is willing to amend the Criminal Justice Bill to abolish the offences of blasphemy and blasphemous libel.

The High Court last month refused to allow a prosecution of the director general of the BBC for blasphemy over the screening of the controversial musical, Jerry Springer - The Opera.

In 2006, Parliament passed the Racial and Religious Hatred Act, which creates an offence of inciting or “stirring up” hatred against a person on the grounds of their religion. But the act was so watered down during its passage through Parliament that its critics fear it will be almost useless.

Dr Williams said: “It is clear that the old blasphemy law is unworkable and that its assumptions are not those of contemporary lawmakers and citizens overall. But as we think about the adequacy of what is coming to replace it, we should not, I believe, miss the opportunity of asking the larger questions about what is just and good for individuals and groups in our society who hold religious beliefs.”

Dr Williams was criticised by the National Secular Society who accused him of promoting “self-serving and dangerous” ideas.

Terry Sanderson, president, said that the Archbishop’s speech was a “blatant pitch for new legislation to replace the blasphemy laws that the Government are planning to scrap.”

The Government is at present consulting the Church of England about its plans to repeal the blasphemy laws before introducing the changes when the Criminal Justice Bill is in committee stage in a few weeks.

“It is as if the prolonged and widespread debate on the recently-introduced religious hatred legislation had never happened,” said Mr Sanderson. “Dr Williams takes us right back to the beginning with his special pleading for the protection of religious feelings – in other words, another form of blasphemy law that would be even worse than the one we’re about to ditch.”

Mr Sanderson pointed out that the Racial and Religious Hatred Act – which had been under consideration for five years - was now on the statute book. “It was enacted only after a great deal of bitter dispute between religious interests and those who feared for free speech,” he said.

“There is also now in law a concept of religious aggravation that can be applied to some public order offences. It carries a potential prison sentence of seven years. This is draconian and extreme by any measure – and now the Archbishop appears to want something else.”

Mr Sanderson said that the Archbishop appeared in his speech to be making excuses for those who rioted about the Salman Rushdie case and threatened the author with death. He also seems to think that those who created lethal street protests over the Danish cartoons had a point. “The Archbishop’s speech is, at base, self-serving and dangerously illiberal,” Mr Sanderson said. “We certainly hope that the Government is not now going to bring forward something even more extreme as a quid pro quo for abolishing blasphemy.”