One in 11 boys leaves primary school 'unable to read'
One in 11 boys in England - one in seven in some areas - starts secondary school with, at best, the reading skills of an average seven-year-old.
According to data obtained by the BBC's Today programme, 9% of 11-year-old boys fell well below expected standards.
But in Nottingham that proportion was 15% and the situation was only marginally better in Derby, Manchester, Rotherham and Telford.
The government is bringing in a reading check for six-year-olds.
Education experts said it was hard for children struggling at age 11 ever to catch up.
Just before leaving primary school, children take a reading test as part of their Sats examinations. They are then marked into categories, level 4 being the expected standard.
According to the Department for Education statistics, the proportion of children gaining that grade has increased dramatically over the last 15 years, from 49% to 81%.
But this masks a stubborn problem at the lower end of the school spectrum. In 1995, the proportion of 11-year-olds getting Level 2 or below in English - the standard expected of a seven-year-old - was 7%. In 2010, it had fallen only to 5%.
The figures show the problem is worse for boys. Overall in England, 9% of them - about 18,000 - achieved a maximum of level 2 in reading.
In some local authority areas that proportion was far higher: 15% in Nottingham, 14% in Barking and Dagenham, Telford and the Wrekin, Rotherham, Manchester and Derby.
Dylan William, professor of education at the Institute of Education, said it could be very hard for children struggling with their reading to catch up.
Secondary school teachers are not used to teaching children who cannot read properly, because the syllabus is based on textbooks.
Prof William said it had never been more important to be able to read to a decent standard.
He explained: "Twenty years ago, you got a lot of information from television. Now it's the internet - you have to be more literate."
But Prof William says that will not, in itself, tackle the issue: "Identification is not the problem. If you ask the teachers of those boys who are struggling at 11... they probably were identified as having problems at seven.
"The problem is finding the resources to deal with it."
He says there are solutions, known as "reading recovery" methods. They include intensive tuition and much smaller class sizes.
But these methods tended to be expensive, he said.
If it was girls who were having this very problem, and not boys, would anybody dare suggest that it was just too expensive to bring the girls up to speed?