News: relaxing planning restrictions on the green belt would destroy London's vitality "even more surely than it would despoil the countryside," architect Richard Rogers has warned.

"I do not say this as a rural nimby, though I treasure England’s natural landscape, but as a defender of cities," writes Rogers in the London's Evening Standard newspaper, arguing that the city's mix of jobs, shops, restaurants, parks and nightlife acts as "a magnet to people from across the globe."

"Letting the city sprawl would undermine this mix and intensity, reversing the rebirth of city-centre living," he warns, saying suburban sprawl not only leads to "social atomisation" but becomes "environmentally disastrous" as car journeys displace public transport.

To solve the UK's housing crisis, architects, planners and developers "need to show ingenuity" by redeveloping thousands of hectares of brownfield land as well as empty offices and houses across the country – but simply converting buildings is not enough, he argues.

"It will not create homes or communities unless intelligent urban design and planning also create the schools, shops and public transport hubs civilised life demands.

"And why should we rush to convert office blocks when we already have three-quarters of a million homes in England lying empty, and sites with planning permission for 400,000 more?"

According to homeless charity Shelter, the government's plan to build 150,000 "affordable" homes – priced below market rates – over four years will provide less than a third of what is needed, with over 1.7 million households currently on local authority housing waiting lists.

UK planning minister Nick Boles recently called for an area of countryside twice the size of Greater London to be built on in order to solve the growing housing crisis.

In the US, New York mayor Michael Bloomberg last year announced plans for "micro-unit" apartments to help solve the shortage of small homes in Manhattan, while San Francisco city chiefs have voted to allow the development of apartments as small as 20 square metres.

Rogers' firm recently completed a set of six-sided apartment blocks beside the Tate Modern art gallery in central London – see all projects by Rogers Stirk Harbour + Partners.

Photograph by Andrew Zuckerman.