It’s now official – the United Kingdom is no longer a Christian majority country. This is the headline from the 2021 census data on religion in England and Wales (not Scotland, more on that later), although the more conservative papers may go for “Christianity still the largest religion in Britain”. Which is also true, but it is the first headline that will garner the most attention because the idea of secularisation – basically the idea that religion is in decline in modernity – is so entrenched in how we think about religion in the modern world.

But for those of us who have been geeking out about this data since the question was first asked in the 2001 census, the immediate takeaway is how little there was here that was a surprise. Almost everything in the 2021 census was predictable from comparison of the 2001 and 2011 censuses.

72% of the population of England and Wales (37.3 million) identified as Christian in the 2001 census. This fell 13% in the next decade, when 59% (33.2 million) ticked that box. In the last decade, it fell by exactly the same amount – 13%, to 46.2% (27.5 million people). So while it is less than half for the first time, the trajectory was entirely predictable, and importantly, steady. It all suggests that “no religion” will overtake Christianity to become the largest religious identification by the next census.

It is important to note that this question is focused on religion as identity. There is no question about what one does, or indeed what one believes. None of these three things is “really” religion any more than any of the others, but it certainly complicates things. A person might identify as Christian who doesn’t believe in God or go to church, and equally someone with “no religion” might pray or regard themselves as spiritual. The video below discusses why this is important for interpreting census data.

So is this a decline of institutional religion? Well, yes and no. There were slight increases to the percentage of the population identifying as Jewish, Hindu, Sikh and Buddhist, and “Other”. The largest of these was for Islam, which rose from 4.9% to 6.5%, or around 800,000 people. Not only is that a far smaller percentage of the population than most people realise (encouraged by the right-wing press), but it in no way explains the nearly 6 million who no longer identify as Christian, the vast majority of whom now ticked “no religion” (37.2% in England, but 46.5% in Wales). Scotland has yet to publish its results, but it is likely to be higher still, as already in 2011 Christianity stood at 51%, and no religion at 37% (source).

But on the other hand, in the UK context, Christianity is the epitome of “institutional religion” – the monarch is the head of the Church of England, and its functionaries are in the House of Lords and other parts of the legislature. So identifying as Christian hits differently than identifying as a minority religion – one marks one as a member of an oppressed or marginalised community, the other as a member of the British Empire. Which is to say, when looked at in that way, it is understandable that a rejection of institutional religion really only affects certain religious institutions.

Perhaps the most likely factor, however, is simply that the default option has changed. Whereas only two decades ago, three-quarters of English people were content to tick the box for Christianity, now fewer than half are. But it’s hard to see evidence that our lifestyles have changed all that much. Maybe the thing that has changed the most is that people, especially younger people, are no longer inclined to say Christianity when really they don’t particularly care.

So, does the census result show that religion in the UK is changing? Probably, though how much depends on what we mean by “religion”.