The 75-year-old is unafraid of confronting parents while he cycles around London. Sometimes he leans into the open windows of four-wheel drive vehicles to talk to mothers who are dropping children off at school. He tells them that in their concern to minimise the risk for their child, they are exposing others to greater risk.

He cheerfully admits that his argument is usually met with a two fingers gesture.

Dr Hillman, a senior fellow at the Policy Studies Institute, spoke on the topic at the Royal Geographical Society conference in London last week.

“Chauffeuring children denies them physical exercise, it denies them exposure to small risks that I think is an essential part of growing up,” he said.

His classic study One False Move, carried out with John Adams and John Whitelegg, revealed that the number of 7- and 8-year-olds getting to school on their own dropped from 80 per cent in 1971 to 9 per cent in 1990.

But Dr Hillman told The TES he believes the chauffeuring culture will end, not because of the growing concern over children’s confined lifestyles but for the need to tackle climate change.

“Better to interfere with parental choice than add to the damage to the planet,” he said.