A LACK of affordable housing is increasing the emotional and financial burden on parents as grown-up children can no longer afford to move out.

Three out of ten parents (27%) have at least one adult child aged between 21 and 40 living at home, according to new research.

Two-thirds of parents with at least one adult child living at home say they are doing so because they simply can't afford to move out, it found.

The ComRes poll of more than 1,100 parents with adult children was conducted on behalf of the National Housing Federation.

Some 89% of parents with grown-up children believe there is not enough housing in Britain that people can afford, it reveals.

While one in four parents said having grown-up children living at home had brought their family closer together, other parents were not so positive.

One fifth (23%) said having a grown-up child living at home had caused them stress, with a further fifth (18%) saying it had caused family arguments.

Some 8% of parents said having a grown-up child living at home had caused them to fall into debt.

National Housing Federation chief executive David Orr said the research showed that so-called "empty nest syndrome" was becoming a thing of the past.

"Rather than waving their children off as they grow up and move out, parents are stuck with kids in their thirties still living at home," he said.

"Moving out and setting up a family home of your own is a normal rite of passage. Yet as rents, mortgages and deposits continue to soar out of reach, it is no longer an option for many.

"We're delaying adulthood for grown-ups kids who are left stuck in their childhood bedrooms.

"As a result parents are also trapped, unable to move on with their lives and benefit from the freedom which comes when their sons and daughters move out."

As a country, Britain needed to build more homes at the right prices in the right areas now to ensure there is another option, said Mr Orr.

"We must encourage more development of new homes and the decisions about where more homes are built are being made locally, by local councillors.

"They will act if local people say they want more homes in their local communities.

"Unless local communities speak out in favour of more homes, mums and dads across the country will be stuck providing a roof for their adult children."

Parents in higher income brackets are more likely to have at least one grown-up child at home.

More than one third (41%) of parents with at least one adult child living at home said they were doing so because the cost of living away from home is too high.

A further fifth (22%) say they are living at home while they save up for a deposit.

The National Housing Federation believes that unless more homes are built, the situation soon could become even bleaker for parents with children in their twenties and thirties.

First-time buyer house prices are set to increase by 42% by 2020, while rents in 2020 will be 46% higher that they are today, said the federation.

That meant parents could be forced to look after their grown-up children for even longer as they struggle to save up enough money to get a place of their own.

The federation's Yes to Homes campaign is calling on local people that want more affordable homes in their communities to contact their local councillors and support more housing.