The urban planning ideas of King Charles – which once saw him battling with the architectural establishment – are helping to inspire the next generation of new towns in England, imminently expected to be announced by the government.

A housing ministry official told a King’s Foundation event about plans for new towns that share much in common with the King’s traditional town-building philosophy.

The 12 new towns will be walkable and environmentally friendly, with “gentle density” such as “terraced housing and mansion blocks” rather than high-rise.

TV architect George Clarke says the King’s views on buildings have now become part of the mainstream.

“He was absolutely slammed down by the architectural establishment,” said Clarke of the King’s attacks on some modern design plans, such as in 1984 calling a proposed extension to the National Gallery a “monstrous carbuncle”.

But Clarke says there has been a sea-change and younger architects are much more empathetic about producing buildings that are sensitive to the local place and the likes and dislikes of the public.

“Let’s be honest, the enormous mass of 1960s brutalism was devastating for parts of Britain,” said the TV presenter.

“Too many modern designs had been ‘ego-driven’ and the architectural arrogance was off the scale,” he said.

Clarke now warns that too many people are having to “mortgage themselves up to the hilt” for homes on new estates that are not always well built and with poor access to local services.

“I would live in one of the King’s houses on one of his estates, which are really well designed, traditional pieces of architecture, sustainably done, high quality windows, with beautiful public spaces, places for kids to play, pedestrianised areas, village greens,” said Clarke.

The TV architect grew up in council housing in a new town, Washington, in the north-east of England, which he said was a “very humane piece of design”.

“It wasn’t streets in the sky. It wasn’t concrete carbuncles, it wasn’t anything ugly like that. There were simple, low density houses, amazing landscaping, brand new highways,” which he said provided a “fantastic place to live”.

The King’s support for traditional building styles, and his idea of “harmony” with nature, have helped to shape his own new town schemes, including Poundbury in Dorset and Nansledan in Cornwall.

They emphasise a walkable layout, using local building materials and creating public spaces which help to support a sense of community.

Although the traditional style had been attacked by some critics as inauthentic and backwards looking.

The government said it had received more than a hundred proposed sites for new towns, each expected to have a population of 10,000 or more, as part of its drive to create 1.5 million new homes.

The final selection of locations is expected to be revealed very soon, and the housing ministry set out the challenges and the framework for how they might be designed.

Previous waves of new towns had been “responses to overcrowding and economic imbalance in the post-war period; they offered affordable homes, green spaces and a sense of community”, the ministry said at an event run by the King’s Foundation, a charity which promotes sustainability and protecting traditional craft and building skills.

Post-war new towns “taught us very hard lessons” about being built too much around cars, a lack of maintenance of public spaces, poor transport links, a lack of social life and insufficient jobs, they added.

The new towns will have a “design code” for buildings to create an identity. They will be walkable, with a goal of “environmental sustainability”, and with a significant proportion of affordable housing, said the ministry official.

This will mean a “compact” design with “higher density, but not necessarily in the form of high-rise buildings, but gentle density models that we are familiar with, such as terraced housing and mansion blocks,” she said.

The purpose was to turn “housing into homes and sites into communities”, she said.

The King’s Foundation event, held at Hatfield House, heard from more planners about how other new developments had been inspired.

Robert Davis, founder of Seaside, Florida, which was used to film The Truman Show, highlighted influences that included the Regency designs of Bath, Renaissance Siena and the ideas of King Charles.

The serious social consequence of town planning was emphasised by another US speaker, Jim Brainard, mayor of Carmel, a town in Indiana, which he’d helped to re-design as it expanded.

It had been a town without any centre or public places where people might gather, he said, a problem for this “fractured republic that we have in the United States today, with so much partisanship”.

“It’s so important for people of different backgrounds, different faiths, different races, different religions, to have a place to come together, to get to know people who have different backgrounds.

“Those types of interactions have taken place in town centres forever,” he said.