The review, led by Shadow Cabinet member David Willetts, came in response to a Unicef report last year that ranked Britain the least child-friendly of 21 rich nations.

Launching it at the Charles Dickens Primary School in Southwark, south London yesterday, Mr Cameron said: “My ambition is that Britain goes from being the worst place to bring up children to the best.

“The Government can’t admit that they have got some things wrong. We need to do more.

“We don’t just need better playgrounds, we need to make sure they are better supervised. That means more community police officers and park wardens.

“We need to reclaim the street, because that’s where our children grow up.”

Britain’s parkies inspired loyalty and respect, and author Nick Butterworth created a much-loved children’s book series  called Percy The Park Keeper.

But their numbers dropped sharply after parks maintenance was contracted out 20 years ago.

Mr Cameron also said adults must feel free to exert authority over other people’s children, and also to help them, without fear of being taken to court for it.

“This basic social responsibility has been dramatically undermined by a risk-averse health and safety culture which has poisoned the relationship between adults and children,” he said.

Children’s campaigners last night welcomed the Tory proposals. Children’s Society chief executive Bob Reitemeier said: “Learning through play and from making mistakes is fundamental to children’s development.”

He said half of adults say children should not be allowed to play outdoors unsupervised before the age of 14, due to concerns about the modern world.

“What is now required is a wider culture change which tackles the current climate of fear and restores adults’ trust in children and each other,” he added.

Clare Tickell, chief executive of children’s charity NCH, said: “This is a much-needed review.”

Communities Secretary Hazel Blears insisted that parks had improved in recent years and that the introduction of neighbourhood wardens had already helped to reduce crime.

“This Government put a stop to years of disappearing parks and green spaces and successfully turned around that decline in many places. This includes investment of over £24million.

“There are around 340 neighbourhood warden schemes providing a visible, uniformed presence in parks, high streets and other spaces. People are increasingly satisfied with their parks.”