Almost 3.8 million adults aged between 20 and 34 are estimated to still be living with their parents – the highest figure since comparable records began in 1996 – according to new analysis by conveyancing firm Bird & Co.

Using data from the Office for National Statistics and HM Land Registry, the research found that nearly three in 10 young adults now remain in the family home, compared with around one in five three decades ago.

The number of 20 to 34-year-olds living with their parents has increased by more than 40% since 1996, despite the overall size of the age group growing by less than 4% over the same period. Bird & Co estimates that, had young adults continued leaving home at the same rate as in the 1990s, around one million fewer would still be living with their parents today.

The research also found a notable gender gap. Around 35% of men aged 20 to 34 live with their parents, compared with 22% of women, meaning young men are more than 50% more likely to remain in the family home.

Bird & Co believes affordability continues to be a key factor. Comparing deposit requirements with rental costs across 316 local authorities in England and Wales, the firm found that a typical 10% house deposit is now equivalent to around 28 months’ rent. In some major cities, buyers would need to save the equivalent of between 18 and 24 months’ rent, while in parts of London the figure approaches three years’ rent.

The firm said the findings highlight the financial challenge facing many first-time buyers, particularly those already paying high rental costs while trying to save for a deposit.

Daniel Chard, partner at Bird & Co, said: “For the majority of first-time buyers, the principal obstacle is not the monthly mortgage payment but raising the deposit. When that deposit is equivalent to two years of rent across much of the country, and considerably more in the least affordable areas, it is unsurprising that so many young adults are remaining at home. These are the highest numbers on record, and the cost of buying offers a plausible explanation.

“The right decision will always depend on individual circumstances. Anyone considering a first purchase should weigh the full cost of buying a home, including the deposit, mortgage commitments and legal fees, and seek professional advice before proceeding.”