Almost five million adults in England and Wales were living at home with their parents during the latest census, including more than one in 10 people in their early 30s.
Almost a quarter of families had an adult child living in the household during Census 2021, in what the Office for National Statistics (ONS) described as a “continuing trend” rather than as a result of the coronavirus pandemic which was ongoing at the time.
Around 4.9 million adults lived with their parents at that time, a rise of 14.7% from around 4.2 million a decade previously, the latest statistics showed.
Around one in every 4.5 families (22.4%) had an adult child living with them at the time of the census, up from around one in five (21.2%) in 2011.
The ONS said: “Despite Census 2021 being conducted during the coronavirus (Covid-19) pandemic and associated lockdowns, the rise in numbers of adults living with their parents appears to be a continuing trend rather than a result of the pandemic.”
The number of families in England and Wales with adult children living with their parents rose 13.6% between the 2011 census and the 2021 census to nearly 3.8 million.
The ONS said more than one in 10 (11.6%) of adults aged 30 to 34 were living with their parents at the time of the latest census, up from 8.6% a decade earlier.
The statistics body said most people in their early 20s were living with their parents by the time of Census 2021, with the average age of adult children in this situation being 24 – one year older than in 2011.
Just over half (51.2%) of 20- to 24-year-olds were living with their parents in 2021, up from 44.5% in 2011, while the share of 25- to 29-year-olds living with their parents rose from around one in five (20.1%) in 2011 to more than one in four (26.7%).
The ONS defines adult children as anyone who is considered a non-dependent child, who is over the age of 18, living with their parents and does not have a spouse, partner or child living with them.
Anyone aged between 16 and 18 who is not in full-time education and does not have a spouse, child or partner living with them is also included.
The number of lone-parent families with adult children increased by more than a fifth (22.4%) in England and Wales between 2011 and 2021.
Men outnumbered women by about three to two (60.8% and 39.2% respectively) when it came to living with their parents.
The ONS said this was a similar split to 2011 (61.6% and 38.4%).
The number of families with adult children at home increased in every region of England and Wales in the 10-year period, with the fastest rise in London, at 24.5%.
The ONS said this was around twice the increase seen across all other English regions combined and around five times the increase seen in Wales.
It added that, according to its recently published bulleting on housing affordability in England and Wales, London was the least affordable region for buying a home in 2022, with an average worker spending 12.5 times their annual earnings to buy a home where they work.
The capital was also the least affordable region for private rental housing in 2021, with the average rent equivalent to 39.8% of average household incomes, according to the ONS bulletin for 2021 private rental affordability.
Meanwhile, separate figures from the ONS about families in England and Wales found the total number of single-parent families has risen.
The total number at the time of the census in 2021 was 3,168,080, up from 2,892,290 in 2011.
More families had only non-dependent children in 2021 compared with 2011 (17.1% compared with 15.8%) and fewer families had dependent children (41.5%) compared with 2011 (43.0%).
Four in 10 (41.3%) of all couple families had no children.
The ONS said a higher proportion of lone parents were aged 50 and over in 2021 (41.8%) than in 2011 (33.4%) and fewer lone parents were aged 24 and under in 2021 (3.6%), compared with 2011 (7.5%).
A lone parent was defined as a family with one male or female parent living with one or more dependent or non-dependent children.