Richard Dawkins has said that Catholics who do not believe in transubstantiation - the doctrine that the bread and wine become Christ's body and blood during the Mass - should admit that they do not truly follow the faith.

The atheist author and evolutionary biologist made the remarks in Dublin, during a public interview as part of the city's Writers Festival.

The Irish Times newspaper had run a poll with Ipsos/MRBI which found that 62 per cent of Catholics said the bread and wine "only represents" the body and blood of Christ. By contrast, 26 per cent said that they believed it physically transformed.

“If they don’t believe in transubstantiation then they are not Roman Catholics,” Dawkins told the audience in the National Concert Hall. “If they are honest they should say they are no longer Roman Catholics.” Asked about the results of the poll, he said: “I wouldn’t hold back on the ridicule”.

Dawkins's comments provoked a riposte from columnist John Waters in the Irish Times about the "ideological smugness" of those questioned in the poll. He wrote:

Does “rationality” involve a requirement to understand the processes you claim to believe in or trust? If so, how many people could tell you, off the top of their heads, that the margin of error in any particular aspect of an opinion poll is calculated by multiplying by two the square root of the result obtained when the quantum at issue is multiplied by 100 minus itself and the answer divided by the sample? Give me transubstantiation any day – much easier on brain, mind and reason.

Dawkins's comments on the situation in Ireland follow similar remarks on the religiosity of Britain. In his guest-edit of the New Statesman magazine in December 2011, Dawkins wrote about the findings of a UK poll commissioned by the Richard Dawkins Foundation for Reason and Science which showed that 54 per cent of those surveyed described themselves as Christian. He described them as "Census Christians", for only a third ticked the box because of their religious beliefs.

He added: