The number of people who say they have no religion is rapidly climbing and significantly offsets the Christian population in England and Wales, new analysis shows.

The proportion of the population who identify as having no religion – referred to as "nones" – reached 48.5 percent in 2014, almost double the figure of 25 percent in the 2011 census, The Guardian newspaper reported.

Those who define themselves as Christian – Anglicans, Catholics and other denominations – made up 43.8 percent 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 Twickenham told the newspaper.

Bullivant analysed data collected through British Social Attitudes surveys over three decades.

"The main driver is people who were brought up with some religion now saying they have no religion. 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 did not examine data from Scotland or Northern Ireland, but The Guardian reported that last month a Scottish Social Attitudes survey found that 52 percent of the population said they were not religious, compared with 40 percent in 1999.

RELIGION IN NORTHERN IRELAND

In Northern Ireland, which has long been the most religious part of the United Kingdom, 7 percent said in the 2011 census that they belonged to a non-Christian religion or no religion.

The new analysis will fuel concern among Christian leaders about growing indifference to organised religion.

The Church of England said it this year that it expects attendance to continue declining or another 30 years as its congregations age and the millennial generation rejects the institutions of faith.

Bullivant's report, Contemporary Catholicism in England and Wales, is to be launched at Britain's lower chamber of Parliament on May 24 and it finds that both the Anglican and Catholic churches are struggling to retain people brought up as Christians.

Four out 10 adults who brought up as Anglicans define themselves as having no religion, and almost as many "cradle Catholics" have discarded their family faith to become "nones."

The report said that neither the Anglican nor the Catholics are bringing in fresh blood through conversions. Anglicans lose 12 followers for every person they recruit, and Catholics 10.

The vast majority of converts come from other Christian denominations, rather than non-Christians or people with no religion.

"There's a kind of denominational musical chairs," said Bullivant. "No one is making serious inroads into the non-Christian population."

The proportion of the population who describe themselves as Anglican plunged from 44.5 percent in 1983 to 19 percent in 2014. Catholics made up 8.3 percent, other Christians 15.7 percent and non-Christian religions 7.7 percent said The Guardian.

Bullivant's analysis found that London has the smallest proportion of people identifying as "nones," at an average of 40 percent, accounted for by the capital's large minority ethnic population.

Conversely, 59.5 percent of people in Wales say they have no religion.

Half of all Christians in England and Wales are aged over 55, although Catholics have a younger age profile and 58.6 percent of those describing themselves as Christian, are women.

More than nine in 10 Christians are white, which is slightly higher than in the general population. Far more Catholics (27.5 percent) than Anglicans (8.9 percent) attend church once a week or more.

The report is intended to provide reliable up-to-date statistics about the state of Christianity, and particularly Catholicism. It drew on data from British Social Attitudes surveys between 1983 and 2014.