The proportion of people aged 16 or older in England and Wales who are married or in a civil partnership has fallen below 50% for the first time.

The figure dropped to 49.4% in 2022, according to the latest estimates from the Office for National Statistics (ONS).

This was down from 49.7% in 2021 and a reduction from 51.2% a decade earlier in 2012.

The previous release on population estimates by marital status and living arrangements across the two nations covered estimates for 2020, so Thursday’s release is the first showing figures for 2021 and last year.

The ONS said comparable records go back to 2002.

Other data going back to 1972, while not directly comparable, also shows the percentage married had never dropped below 50%.

Couples living together but not in a marriage or civil partnership rose to more than a fifth – from 19.7% in 2012 to 22.7% in 2022, equivalent to 5.4 million people in 2012 and 6.8 million people in 2022.

The statistics suggest laws in this area must be updated and are “crying out for reform”, legal experts said.

David Lillywhite, partner at Burgess Mee Family Law, said: “Unfortunately, many couples still believe that simply by living with their partner they will automatically be entitled to a share of the other’s wealth or receive financial support from them when the relationship breaks down. The reality is very different and can often come as something of a shock.

“This area of law is crying out for reform, which could include the ability for cohabitees to apply for maintenance for a limited period to adjust for the loss of financial support; an opt-out right for eligible cohabitees for financial remedy orders like married couples and civil partners; and a right for cohabitees to inherit under the intestacy rules and be treated the same way as married couples for tax purposes.”

If marriage is no longer the default for modern families, our laws should be updated to reflect that

A review of laws governing how a couple’s finances are divided after a divorce was announced last year, with the Government enlisting the Law Commission to analyse how the 50-year-old laws work in practice.

But Sital Fontenelle, head of Kingsley Napley’s family and divorce practice, said protections for cohabitees, who currently have “limited rights”, must be considered.

She said: “It’s all very well to have started a review of the Matrimonial Causes Act and how finances are divided between separating spouses on divorce, but if marriage is going out of fashion, then the rights of cohabitees and greater protection for their families should be addressed.

“If marriage is no longer the default for modern families, our laws should be updated to reflect that.”

While people in civil partnerships still account for a small proportion of those in a legal partnership, estimates for civil partnerships have almost doubled over the last decade, from 120,000 in 2012 to 222,000 in 2022, the ONS said.

This period covers the introduction of opposite-sex civil partnerships from the end of 2019.

Same-sex marriages have increased, with the estimated number of people in these marriages at 167,000 in 2022, up from 26,000 in 2015.

Of these, males accounted for around six in 10 (61.2%), while females accounted for around four in 10 (38.8%).

Overall, 99.3% of married people were married to someone of the opposite sex.

More than six in 10 (61.3%) of the population aged 16 and over were either living with a legal partner or cohabiting.

Just over a quarter (27.6%) of 16 to 29-year-olds lived in a couple in 2022 compared with more than three-quarters (78.0%) of 40 to 44-year-olds.

People aged 70 and over accounted for almost a fifth (18.3%) of the population who were married or in a civil partnership in 2022 – up from 15.1% in 2012.

Those aged under 30 accounted for 3.2%, down from 4.9% in 2012.

The ONS said the figures reflect an ageing married or civil partnered population over the past decade.

The Marriage Foundation said the continued trend away from marriage is “bad news for couples and bad news for children”.

Its research director Harry Benson said: “Marriage may not be a panacea but it stacks the odds in favour of stable families. Most young adults want to marry at some stage.

“Yet this trend shows we are making it hard for them. Welfare policies make it especially punitive for the lowest earners to marry. It’s nearly a decade since any Cabinet minister made any speech or comment on marriage. Maybe these figures will prompt them.”

A Ministry of Justice spokesperson said: “We are currently reviewing the laws around marriage and divorce and will consider what steps might be taken in relation to cohabiting couples once this work is complete.”