Tens of thousands of seven-year-olds in UK are struggling to master the three Rs, official figures show.
The new statistics reveal that after three years of schooling many UK children can read only the easiest words, such as "cat" or "dog", and do the very simplest sums.
Almost 106,000 seven-year-olds have failed to reach level 2 – the standard expected of the age group – in writing.
More than 83,000 pupils have a reading age of a five-year-old or lower. And over 58,000 children are falling behind the expected standard in maths.
The figures, published by the UK Department for Education, are based on teachers' assessments of pupil achievement at the age of seven.
They show that 85% reached the expected level or higher in reading, 81% achieved it in writing, 90% made at least level 2 in maths and 89% reached it in science. These figures are broadly the same as last year.
The percentages of pupils achieving level 3 – one above the required standard – in each of these subjects has also remained static this year, except in science, where it dropped from 21% to 20%.
The statistics also show that boys are still lagging behind girls.
Nearly nine in 10 (89%) seven-year-old girls reached level 2 or higher in reading, compared with 82% of boys.
In writing, 87% of girls scored at least level 2 compared with three-quarters (76%) of boys, and in maths there was a gap of three percentage points, with 91% of girls achieving the expected level against 88% of boys.
UK Coalition Schools minister Nick Gibb says: "These figures show that many children are doing well. But it is worrying that there are still so many who are behind just three years into their school careers.
"Success in later life is founded on an understanding of the 3Rs in the first few years of school. Problems must be identified at a young age and rectified before it is too late."
There is also a gap in achievement between children from disadvantaged backgrounds and their more affluent classmates. Just two-thirds (67%) of pupils on free school meals (FSM) – a measure of poverty – reached level 2 in writing, compared with 85% of all other pupils.
And while 88% of all other pupils reached the expected standard in reading, the same was true for only 73% of children eligible for free dinners.
In maths, 81% of FSM pupils reached level 2 compared with 92% of other youngsters.