English Partnerships (EP) is to require that houses built on its sites offer greater space.

Launching the development agency’s annual report this week, John Walker, its chief executive, said the agency was drawing up a new version of its quality and price standards that developers must comply with if they want to build on EP sites.

Developers should not place pressure on designers and contractors to inflate the density of development beyond what they believe a site can bear, according to a RIBA report.

Meanwhile, the RIBA’s housing manifesto, published last week, says that density levels should be tailored to site conditions. It says: “Developers must not place pressure on designers and constructors to maximise density irrespective of site conditions or constraints.”

It adds that such pressures have led to a proliferation of one and two-bedroom properties in inner city areas, many of which are being left empty by buy-to-let investors.

The manifesto also calls for the introduction of minimum space standards in England and Wales. It says the extra costs involved in building larger homes would be counter-balanced by savings achieved through greater use of off-site manufacturing and economies of scale .

It says that the average new dwelling in England and Wales has a floorspace of 76m2 compared to 115m2 in Holland.