The advice signals a reversal of views for Biddulph, an Australian with more than 20 years’ experience as a therapist, whose previous bestsellers
include Raising Boys and Raising Girls.

In his new book Biddulph will admit he has changed his mind because of growing evidence of increased aggression, antisocial behaviour and other problems among children who have spent a large part of their infancy being cared for away from home.

He argues that such children may have problems developing close relationships later.

The criticisms by Biddulph and other experts are likely to bring them into conflict with the government, which has made expanding nursery places a key part of its family policy.

In Britain nearly 250,000 children under three attend nurseries full or part-time. Worldwide, the number of babies and toddlers being cared for in nurseries has quadrupled in the past decade as mothers increasingly return to work.

Labour has created more than 1.2m new childcare places for the youngest children since it came to power in 1997. Every child aged three is entitled to a free nursery session of 2½ hours a day and the government has carried out pilot schemes to extend these sessions to two-year-olds, part of the age group that is Biddulph’s greatest concern.

Gordon Brown, the chancellor, has promised an extra £769m for early years state childcare between 2005 and 2008, while the government
proposes to extend maternity and paternity leave, which makes it easier for women to keep their jobs after they have children.

Biddulph admits he started out as a believer in quality nursery care and the role it played in broadening women’s lives but says he has found reality never matched the fantasy. “In fact it was often a disastrous disappointment,” he said.

“The best nurseries struggled to meet the needs of very young children in a group setting. The worst were negligent, frightening and bleak — a nightmare of bewildered loneliness that was heartbreaking to watch.”

Biddulph focuses his warnings on what he estimates is the 5% of British parents who “slam” their children into nursery for a large part of their day from the age of six months.

He believes nothing can provide an equal substitute for one-to-one care for a child under two, ideally by a parent. He argues that infants’ brains need to be stimulated by loving interaction if they are to develop properly.

Nannies, he says, can work well as a halfway solution but only if parents are “extraordinarily lucky” with the person they find. He says, however, that care by family or friends is “a much safer option”.

Biddulph says it was five years ago that he began writing his book, Raising Babies: Should Under 3s Go To Nursery?, published next month by Harper Thorsons. But he he was initially afraid to release it because its message was “so confrontational, so against the tide”. He points, however, to increasing evidence supporting the thesis.

Last year Penelope Leach, an authority on childcare, issued a similar warning after finding that young children looked after by their mothers did better in development tests than those cared for in nurseries, by childminders or relatives.

The study of 1,200 children for London and Oxford Universities by Leach, Kathy Silva and Alan Stein — both Oxford professors — suggested babies and toddlers who had spent time in nursery care had “higher levels of aggression” in later childhood.

Biddulph cites two other studies that have found evidence of antisocial behaviour and violence among children who have spent long periods in nurseries.

His greatest concerns centre on the group many childcare professionals call the “slammers”, whose children are placed in full-time nursery care from 8am to 6pm before the age of six months and stay there until they go to school. They consist mainly of urban professionals and account for 100,000 of the 2m under-threes.

“Sliders”, by contrast, who make up 35% of British parents, put their children into nursery after the age of two and usually do so part-time, while 60% of parents do not use nurseries at all.

Jay Belsky, director of the Institute for the Study of Children, Families and Social Issues at Birkbeck College, London University, said the evidence on nurseries was far from clear-cut, although for over-threes the findings were more positive.

“Long hours in childcare settings early in life, especially in groups, seem to foster aggression and disobedience. But good-quality childcare for three and four-year-olds seems to have cognitive and linguistic benefits, especially for children from poorer backgrounds.”

Belsky is worried about the cumulative effect of children being raised in nurseries. A classroom full of children who had spent long periods in daycare might be difficult to manage. “Babies need a devoted care-giver,” he said.

An education department spokesman defended childcare policies, including two bills going through parliament, one placing a duty on councils to provide more childcare provision and another extending parental leave. “We are not telling parents what to do but we are trying to provide them with choices,” he said.

“We want to make sure every parent has access to high-quality, safe, stimulating and affordable childcare, so they have greater flexibility in how they balance their lives.”

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