Professor Dawkins said the UK should not pay for the Pope's visit
Leading atheist Richard Dawkins has backed a campaign to have the Pope arrested for "crimes against humanity" when he visits the UK later this year.
Professor Dawkins said he "whole-heartedly" backed the initiative led by atheist Christopher Hitchens.
UK human rights lawyers are preparing a case to charge Pope Benedict XVI over his alleged cover-up of sexual abuse in the Catholic church.
Dr William Oddie, former editor of The Catholic Herald, labelled it "lunatic".
Campaigners hope to cast a shadow over the Pope's planned visit to the UK in September - the first visit by a Pope since 1982.
Prof Dawkins wrote on his blog: "I am optimistic that we shall raise public consciousness to the point where the British government will find it very awkward indeed to go ahead with the Pope's visit."
And writing in the Guardian on Tuesday, columnist George Monbiot wrote: "Picture the pope awaiting trial in British prison, and you begin to grasp the implications of the radical idea that has never been applied: equality before the law."
The BBC's religious affairs correspondent Robert Pigott said the anti-Pope campaign could be seen as a mischievous attempt to create an "air of criminality" around the Pope.
"The controversy over alleged Papal involvement in the cover-up of child sex abuse is providing atheists with a stick with which to beat religion," he said.
The Pope's visit was announced shortly before allegations surfaced that he had signed a letter which delayed the punishment of a paedophile priest in the US.
This followed a series of child abuse scandals involving the Catholic church in the US, the Irish Republic, Germany and Norway.
The Vatican has defended the Pope, saying the Pope is willing to meet more victims of clerical abuse, while the Church has published an internet guide as to how bishops deal with accusations of sexual abuse.
The Vatican said the Pope would not resign over the scandal
Barrister Geoffrey Robertson and solicitor Mark Stephens are considering whether they could either ask the Crown Prosecution Service to initiate criminal proceedings against the Pope; launch their own civil action or refer his case to the International Criminal Court.
Author Christopher Hitchens said he does not believe the Vatican to be a legal state which raises questions as to whether the Pope, as head of state, could claim diplomatic immunity.
He said: "The UN at its inception refused membership to the Vatican but has allowed it a unique "observer status", permitting it to become signatory to treaties such as the Law of the Sea and (ironically) the Convention on the Rights of the Child, and to speak and vote at UN conferences where it promotes its controversial dogmas on abortion, contraception and homosexuality."
The group have cited as precedent the recent case of Israel's former foreign minister Tzipi Livni, who cancelled a visit to London after a British judge issued an arrest warrant over her alleged involvement with the conflict in Gaza.
But Dr Oddie, former editor of The Catholic Herald, said the campaign demonstrated how "wonderfully lunatic" both Christopher Hitchens and Professor Dawkins were.
"What's lawful is what is lawfully agreed by lawful authorities, in this case Italian law - the government of Italy - and secondly, international law, determined by the United Nations. Both legal authorities accept the Vatican is a legal state.
"Christopher Hitchens is entitled to say it shouldn't be one, but he can't say it isn't one - it's like people in a lunatic society saying they are Napoleon," he said.
The Vatican has ruled out any possibility of a papal resignation over the scandal.