Statistics from the Department for Education show that 53 per cent of boys have not reached a "good level of development" by five, compared to 35 per cent of girls. Combined, the figure is 44 per cent.
Children are assessed by teachers to see if they can carry out basic skills like writing their name and reciting letters of the alphabet.
Yesterday, a leading public health adviser warned that the life-long impact of failing to reach this earliest of grades was "horrendous".
Sir Michael Marmot, professor of public health at University College London, said: "Only about 50 per cent of children are rated by their teachers as having achieved a good level of development by the age of five.
"You know what that means? Poorer level of early school development; poorer performance at every school stage; lower status; living in a poor area.
"It all starts at the beginning of life and works through the life course. This is horrendous really."
Those who failed at school also tend to live shorter lives that are blighted earlier by disability.
A year ago Sir Michael unveiled a review, called Fair Society, Healthy Lives, into how to even out the differences in people's health across geographical areas and social classes.
Giving pre-school children "the best start in life" was the highest priority recommendation, as targeting them has the biggest effect.
Sir Michael proposed increasing spending on this age group with measures such as "more parenting support programmes, a well-trained early years work force and high quality early years care".
The work we are doing at Small Talk Speech & Language Therapy and Smart Talkers pre-school groups is all aimed to address these issues. We have a comprehensive package of programmes and activities to train staff by demonstration, help parents and above all share examples of good practise to benefit the children. For more about us www.private-speech-therapy.co.uk and www.smarttalkers.org.uk.
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