When is a Christian not a Christian? The answer may be: “when Richard Dawkins says so.”

That is unfair, but only slightly. The main thrust of the extensive research study he has just published exploring the size and nature of the UK Christian community is that many of those people who ticked the Christian box in the 2001 (and 2011) census are not really Christian.

The charitable interpretation of this is that it states the bleeding obvious. There are a lot of nominal Christians in Britain. Who would have thought it? The uncharitable one is that the eminent atheist is deflating the number of Christians in Britain for his own narrow, partisan reasons.

That there is widespread Christian nominalism in the UK has rarely been in doubt (just read what Robert Tressell has to say about popular Christianity in The Ragged-Trousered Philanthropists published nearly 100 years ago if you doubt this). Dawkins’s survey supports this but in a mixed and confusing way.

Certainly it is noteworthy that fewer than three in ten (28 per cent) “census Christians” say they are so “because they believe in the teachings of Christianity.” But it is no less noteworthy to read that 44 per cent of census Christians’ believe that Jesus was “the Son of God, the Saviour of Mankind,” and that a third believe he was physically resurrected. Those figures are surprisingly high, even to seasoned religion watchers.

The question is: does nominalism matter, or put another way, is a nominal Christian a real Christian? The Dawkins answer is clearly no. Belief and practice far outweigh how people self-identify. But can we so easily dismiss what people say about themselves?

A number of years ago, I conducted a series of in-depth interviews with people who were firmly in Richard Dawkins’s “non-real” camp. Half were nominal Christians, in that they had ticked the relevant box in the 2001 census; the other half had not and were not. Other than that they were identical. None of them went to church, read the Bible, prayed, believed or knew much about Christianity.

And yet there was a palpable, sometimes visceral difference between groups. The census Christians were generally positive, supportive and sympathetic to Christianity and, in particular, its role in British life, whereas the others were hostile to the point of vitriolic about it. In other words, nominalism mattered and we should be reluctant to dismiss it outright.

There is a pleasing irony in this story. Jesus spent much of his short ministry in a pitched battle with the Pharisees, the religious thought-police of the age, who expended great energy in monitoring Israel’s theological boundaries, condemning those who flouted them by working on the Sabbath or failing to maintain food and purity laws as punctiliously as they did. Jesus incensed them by redrawing the boundaries not only to include those left out in the cold but also to banish those who were smugly pious in their religious self-righteousness.

The lesson remains instructive. We do not have windows into one another’s souls and all of us—whether it is Christians inflating the figures and their significance or atheists deflating them—should think very carefully before pronouncing on how many real believers walk among us.

This article was first published in Prospect