By the age of 22 months, children from poor backgrounds are likely to have fallen behind their middle-class peers in developmental terms.

Their talking, listening and social skills will be less well developed and they will recognise fewer words. By the time they are 4, poor children are likely to have heard 13 million words. For a child from an affluent home, the number is 45 million.

Beverley Hughes, the Children’s Minister, frequently cites this research to justify her hardline approach to early-years education and to underscore her determination to eradicate childhood inequality.

The thinking goes like this: if working-class children fall behind because their families, however caring, are unable to give them the same opportunities for learning as the middle class, then the State should try to provide those opportunities at school and in early-years education. Ms Hughes expanded on this view in a statement to The Times yesterday: “We want to ensure that every child gets the best start in life. Evidence shows that early education has a powerful and sustained impact on children’s learning until the age of 10. The Early Years Foundation Stage is not a formal curriculum, it is a play-based approach to learning, development and care for young children.

“It will encourage every young child to reach their full potential, just as any good parent would do for their child at home.”

But there is now a growing body of research to suggest that this approach may not be the best one. Last week, Lillian Katz, Professor of Education at the University of Illinois, argued against the “hothouse” approach to education, which teaches children to read at the age of 4, suggesting that such children did worse at school later on. The founders of the Open Eye campaign, launched in this paper today by a group of child-development experts, share these concerns.

“An early ‘head start’ in literacy is now known to precipitate unforeseen difficulties later on,” they say. A far better approach, they argue, is to allow children to develop through play and practical experience, until they are ready for book learning at 6 or 7 – the practice in many other countries.

What the campaign is calling for is a softer approach from the Government, which would reduce the new early-years foundation state framework to “professional guidelines” free of legal compulsion.

In the light of the research from Professor Katz and others, it seems the only sensible course. And they are right to reject the Government’s insistence that there will be “flexibility” within the new system. As Richard House, a founder of the Open Eye campaign, says: “Two to three years down the line, some new minister may come along wanting to make their mark and they will say, ‘No flexibility’. Then, where will we be?”

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