Proportion of atheists in the ‘non-religious’ category in UK
The proportion of atheists in the ‘no religion’ category is not easy to determine. So I’ve added a red dotted line at half the no-religion trend line to indicate the likely atheist population. This suggests that in the next 20-25 years atheists will be a larger proportion of the population than Christians in the UK.
However the assumption that half of the ‘no religious’ are atheists is questionable because many surveys do not ask about belief. So the respondents are as likely to be expressing their identity as their beliefs. It’s better to think of it as between 40% and 60%.
The lower 40% ‘no religion’ figure is attributable to Linda Woodhead’s research published last year which identified 41% of no religionists as ‘convinced atheists’. (4) Using the ‘Convinced atheists’ category is effectively a measure of those who self-identify as atheists. Many people who are effectively atheist or agnostics do not identify as atheist because of the values they perceive to be associated with it. So the 40% figure is probably an underestimation.
The 60% ‘no religion’ figure comes from Sarah Wilkins-Laflamme’s research which showed 62 per cent atheist, 26 per cent agnostic and 12 per cent unchurched believers in God from BSAS data. (5) This gives much higher figures than most other assessments so I’ve adopted the 60% value as the upper limit.