Islam is the fastest-growing religion in England and Wales, according to new census data that the British government says "describes the defining characteristics of the population, who we are, how we live and what we do."
The latest tranche of data from Britain's 2011 Census was released on December 11. The statistics are for England and Wales only; the census in Northern Ireland and Scotland is separate and the government will release those figures at a later date.
The census data shows that the number of Christians in England and Wales declined by 11% (4.1 million) during the past decade, from 37.3 million in 2001 to 33.2 million in 2011.
During the same period, the Muslim population in England and Wales increased by 80% (1.2 million), from 1.5 million in 2001 to 2.7 million in 2011, making it the second-largest religion in Britain.
The third-largest religion in England and Wales is Hinduism (817,000), followed by Sikhism (423,000), Buddhism (248,000) and Judaism (263,000).
As a proportion of the population as a whole (56.07 million people were counted in the census), the number of those describing themselves as Christian has dropped from 72% in 2001 to 59% in 2011. The number of Muslims has increased from 3% to 5% over a decade.
To be sure, some analysts believe the true number of Muslims in Britain may be much higher than indicated by the census data. This is because the religion question was the only voluntary question on the 2011 Census and 7.2% of people did not answer the question.
It is believed that many of those who completed the census data were reluctant to identify themselves as Muslims and that the true number of Muslims in the country is considerably higher than the 5% indicated by the census data.
The number of people who say they have no religious affiliation jumped by 83%, from 7.7 million in 2001 to 14.4 million in 2011. In proportional terms, this would imply that one-quarter of people in England and Wales now identify as being non-religious.
The census data corroborates information gleaned from other recent surveys. For example, the 2012 British Social Attitudes Survey found that only about half of Britons claim a religious affiliation, down sharply from 20 years ago, when two out of three did. Barely a quarter of young people identify themselves as religious.
If the increase in agnosticism and atheism in Britain is mostly generational, the surge in the number of Muslims is due to immigration and conversion.
The census data shows that during the past decade, England and Wales experienced their greatest-ever population growth (7.1%) in any 10-year period since 1800. Much of this increase is due to immigration.
In real terms, 13% (or 7.5 million) of the population of England and Wales was born abroad. Of that number, 3.8 million arrived between 2001 and 2011. In other words, most of the immigrants living in England and Wales today arrived within the past 10 years.
The census data shows that London is now the most multicultural region in Britain with the highest proportion of people identifying themselves as Muslim, Buddhist, Hindu and Jewish. The northeastern and northwestern parts of Britain have the highest proportion of Christians and Wales has the highest proportion of people reporting no religion.
Knowsley, a borough near Liverpool in northwest England, has the highest proportion of people reporting to be Christian, at 80.9%. Tower Hamlets, a borough in east London, has the highest proportion of Muslims, at 34.5% (nearly seven times the figure for England and Wales as a whole). Norwich, a city in eastern England, has the highest proportion of the population reporting no religion, at 42.5%.
The data shows that 13 of the 20 fastest-growing boroughs are those with high concentrations of Muslim residents, led by Tower Hamlets and Newham in east London. The 2011 Census shows that nearly 40% (or about one million) of the Muslims in England and Wales live in London.
Although immigration is the biggest factor in the rise of Islam in Britain, it is also true that hundreds of Britons are converting to Islam every month.
According to a recent survey conducted by an inter-faith group called Faith Matters, the number of British converts to Islam recently passed the 100,000 mark, and there are as many as 5,000 new conversions nationwide each year. Previous estimates had placed the total number of Muslim converts in Britain at between 14,000 and 25,000.
The survey revealed that nearly two thirds of the converts were women, more than 70% were white and the average age at conversion was just 27.
The survey, conducted by Kevin Brice from Swansea University in Wales, asked converts for their views on the negative aspects of British culture. They identified "alcohol and drunkenness," a "lack of morality and sexual permissiveness" and "unrestrained consumerism."
More than one in four acknowledged there was a "natural conflict" between being a devout Muslim and living in Britain. Nine out of ten women converts said their change of religion had led to them dressing more conservatively. More than half started wearing a head scarf and 5% had worn the burka.
Separately, government authorities recently revealed that an increasing number of inmates at British prisons are converting to Islam. For example, one-third of the inmates at one of Britain's most notorious youth jails are Muslims and the religion is attracting a large number of converts.
Prison insiders say most non-Muslims are locked up during Friday prayers because so many guards are needed to monitor the lunchtime service. As a consequence, many disillusioned youngsters are becoming attracted to Islam by the prospect of getting better food and superior treatment at the prison.
Most conversions to Islam are being triggered by a combination of increasing proselytizing activity by Muslims as well as by a growing disaffection with Christianity.
Some observers say the decline of traditional Christian churches in Britain, a trend that is being accompanied by the demise of Judeo-Christian moral codes in British society, is creating a spiritual vacuum that Islam is beginning to fill.
In any event, all indications are that a growing number of Britons who grew up in nominally Christian households are converting to Islam. This partially explains why the number of Muslims is increasing while the number of Christians is declining.
This trend can be expected to continue. In a study released in 2005, the British-based association Christian Research said that successive generations attend church less frequently than previous ones.
The study, English Church Census 2005, predicted that the number of Christians attending Sunday services in Britain will fall by two-thirds over the next three decades. The study also expected that poor attendance will force some 18,000 churches to close.
At the same time, all indications are that the Muslim population in Britain will continue to grow in the future. At the current rates of growth, the number of Muslims will double again by the time the next census is conducted in 2021, and will then make up 10% of the population.