Many new family homes being built in England are like rabbit hutches because they are too small to live in comfortably, a report has warned.
It found that on average a new three-bedroom home sold outside London is four square metres short of what buyers need – equivalent to the size of a family bathroom.
The study by the Royal Institute of British Architects (RIBA) compared the sizes of new three-bedroom homes on more than 100 developments across England against new, optional space standards introduced in October.
Under these guidelines a three bed, five person home would have a minimum size of 93 square metres. But the report found that outside London, the average size of a new three-bed home was just under 89 square metres.
Those built in Yorkshire were the smallest, at 84 square metres. This meant they were 25 square metres smaller than those in London - a difference equivalent to a double bedroom and family living room.
In London, the South East and the East of England, where properties tend to command higher prices, the average size of a three-bed home was usually bigger than the 93 square metres standard, the report found.
It comes after Chancellor George Osborne last week unveiled plans to build more than 400,000 new homes across England in what was billed as the biggest affordable housebuilding programme since the 1970s.
RIBA president, Jane Duncan, said: "Tiny rabbit hutch new-builds should be a thing of the past. But sadly our research shows that for many people, a new home means living somewhere that's been built well below the minimum space standard needed for a comfortable home.
"We urgently need new homes, but building small homes or cutting corners when converting office buildings to flats is short-sighted and fails the people these new homes are meant to serve."
The RIBA is calling for the national minimum space standard to be included in official nationwide building regulations to ensure that all new homes across the country will be covered.
At the moment they are optional standards that may be taken up by local authorities.
Stewart Baseley, executive chairman of the Home Builders Federation said that overwhelmingly, buyers of new build homes are happy with their houses and how they are designed.
He said that imposing space standards for new homes could make the "acute" housing shortage seen in recent decades worse.