Muslims comprise the youngest religious group across England and Wales, as Christians now account for the oldest at 51, according to official figures.
The latest census data for 2021 shows the average age of Muslims across the two countries is 27.
“This is 13 years younger than the median age of the overall population,” said the Office for National Statistics (ONS), which carried out the survey.
“This religious group has aged since 2011, when the average age for those identifying this was 25 years.
“Of the 3.9 million people who identified as Muslim in 2021, 84.5 per cent were under 50, compared with 62 per cent of the overall population of England and Wales.”
Previously released census data also showed that respondents who identified as Arab, African or South Asian are often significantly younger than other groups in the country.
Other religious groups also registered an increase in average age, with Hindu up from 32 to 37, Sikh from 32 to 37 and Buddhist from 37 to 43, while the average age of people identifying as Jewish was unchanged at 41.
An ageing population and differences in the way people choose to identify were among the factors driving the trend, experts said.
Christians in England and Wales are now on average the oldest group, at 51.
That is six years older than a decade ago, when people describing themselves as Christian were on average 45.
Almost three in 10 Christians are 65 or older, up from just over two in 10 in the 2011 census.
And for the first time, more under-65s say they are atheists than those who identify as Christian.
The ONS last month revealed the proportion of people describing themselves as Christian in England and Wales had fallen below 50 per cent for the first time since such records began.
It said 46.2 per cent of the population described themselves as Christian, down from 59.3 per cent a decade earlier, a decline of 5.5 million people.
People who follow no religion are on average 32, the second-youngest group.
More than half of people in every year from 22 to 30 said they had no religion, with the highest proportion for 27 year olds, at 53.0 per cent.
"Many factors can cause changes in the size of religious groups, including changing age structure, people relocating for work or education and differences in the way individuals chose to self-identify (or how children's religious affiliation was reported) between censuses," the ONS said.
"Politicians should look at today's results and recognise they must renegotiate the place of religion or belief in today's society."
The data shows notable differences between England and Wales.
Among single-age groups, the highest proportion in England with no religion is 52.3 per cent, for both 26 and 27 year olds, but in Wales — excluding the very young — the figure is 66.0 per cent, for those aged 27.
At every age in Wales up to 45, more than half of adults say they have no religion.
In England this is true only of people from 23 to 30.
The proportion of people in England in a single-age group identifying as Christian peaks at 89, at 78.9 per cent, while for Wales it is 99, at 82.1 per cent.
There are also sharp differences among other religious groups.
At every age in England up to 18, at least one in 10 identifies as Muslim, ranging from 11.7 per cent of one year olds to 10.5 per cent of 18 year olds.
But in Wales the equivalent figures for people up to 18 range from 4.5 per cent for one year olds to 3.2 per cent for 14 year olds.
The census allowed people to write in the name of a religious group that was not part of the main list.
Among those who wrote in a group, people in England and Wales who described themselves as "Yazidi" (413) had the youngest average age, at 27.
The oldest was for those who identified as "Brahma Kumari", at 61 — though this is a very small group (235), accounting for less than 0.01 per cent of the population.
Among other small groups, the average age for Rastafarian was 42 (5,950 people); Jain 43 (24,990); Pagan 43 (73,735); Scientology 45 (1,860); Taoist 45 (3,725); and Druid 53 (2,490).2023-01-30T15:33:44Z dg43tfdfdgfd