We don't need a census to tell us that society is changing rapidly. But perhaps we do to quantify just how rapidly. Our latest census is coming up on Tuesday March 5, though it will be a year or so before we get to see its analysis.

The results of the most recent British census from 2011 have just been published and they reveal an astonishing decline in those identifying themselves as Christian - down from 72 per cent in 2001 to 59 per cent in 2011. At the same time those professing no religion rose from 15 per cent to 25 per cent.

Doubtless such large swings reflect changes in perception as to what nowadays defines "Christian". And the big shifts are likely to be at the margins where profession of faith has remained pretty nominal. But they clearly highlight the obvious fact that society is becoming more secular. We can expect the upcoming New Zealand census to expose similar trends.

Now it is entirely appropriate that our democratic institutions, our state education system and our legal system have become, and remain, secular. That is secularism. It has been with us a long time now and was one of the founding principles of the US constitution.