Many family homes being built across England are around the size of a bathroom too small for people to live in them comfortably, a report from the Royal Institute of British Architects (RIBA) has found.
The report raised fresh concerns about "rabbit hutch" new builds after researchers found that on average, buyers of a new three-bedroom home outside London are missing four square metres - equating to the size of a family bathroom - compared with what they need.
The findings were made after the RIBA measured the size of new three-bedroom homes on over 100 developments under construction across England to compare them against new, optional space standards.
New rules were introduced in October, giving local authorities the option to set out minimum space standards for new homes. Under the optional standards, a three bed, five person home would be a minimum of 93 square metres.
But outside London, the average size of a new three-bed home was just under 89 square metres, the research found.
The RIBA described the new space standards as "overly complicated and onerous". Instead, it wants to see a national space standard automatically applied to all homes.
The report found that homes in Yorkshire are by far the smallest in England. It said the average new three bedroom home in Yorkshire is 25 square metres smaller than one in London.
At 84 square metres, the average new three-bed home in Yorkshire is smaller than one on London by the equivalent of a double bedroom and a family living room, RIBA said.
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 tended to be bigger than the optional standard of 93 square metres.
Last week, Chancellor George Osborne unveiled a package of measures aimed at boosting housebuilding and turning "Generation Rent" into "Generation Buy".
The Chancellor's measures promise to be the biggest affordable housebuilding programme since the 1970s, with more than 400,000 new homes set to be built across England.
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 Government must take action to ensure a fairer minimum space standard is applied to all new homes across the country."
The RIBA is campaigning for the national minimum space standard to be embedded within Building Regulations that set the standards for housing design to ensure that all new homes across the country would be covered.
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.
Mr Baseley said: "The industry provides a wide range of house types in sizes and locations that provide choice for people on all income levels. Imposing space standards and so restricting what builders can build takes away choice from home buyers. This would not only prevent more people from buying their own home but also exacerbate the acute shortage of housing that we have experienced over several decades.
"Local elected representatives already have the power to introduce minimum house sizes where justified, and a process is in place to ensure that the needs of households are properly taken into account to deliver the homes the country needs."