The report states: “We would not lose if the more brown parts of the green belt become attractive suburbs like Fulham, Richmond, Clifton in Bristol or Didsbury in Manchester bringing with them a wave of green public space and parks.

“Green belts will hold back our cities, reducing their ability to both regenerate and grow. If we cannot build on green belts we simply build on other green field sites or destroy urban green space.”

The report claims current Green Belt policies are now out of date.

It states: “The problem with the green belt policy at present is that it ignores land quality, so if we are to allow some development in the green belt then we need to protect the more attractive areas that exist within it.”

Alex Morton, author of the report, said: “Building new garden cities sounds radical. But we have successful examples in the UK, from the original garden cities to new towns like Milton Keynes and major planned developments like Docklands and the Olympic site.

“There are significant advantages in concentrating a lot of development in one place, allowing proper planning for infrastructure, and allowing us to create green and pleasant places to live.”