The proportion of the population who identify as having no religion - referred to as 'nones' - hit 48.5 per cent in 2014, almost double the figure of 25 per cent in the 2011 census.
In comparison, those who define themselves as Christian - Anglicans, Catholics and other denominations - made up 43.8 per cent of the population.
"The striking thing is the clear sense of the growth of 'no religion' as a proportion of the population," Stephen Bullivant, senior lecturer in theology and ethics at St Mary's Catholic University in London, told the 'Guardian'.
"What we're seeing is an acceleration in the numbers of people not only not practising their faith on a regular basis, but not even ticking the box. The reason for that is the big question in the sociology of religion," he said.
The report, 'Contemporary Catholicism in England and Wales' will be formally launched at the House of Commons this week.