The government has missed its target for 11-year-olds' attainment in England in their national curriculum tests.
The results trend under Labour
Results of the Key Stage 2 "Sats" tests show that 79% achieved the level expected for their age in English, 76% in maths and 87% in science.
The English result is the same as last year while the other two subjects each showed a rise of one percentage point.
The target - already postponed to this year from 2004 - was for 85% to reach the standard in English and maths.
Education Secretary Alan Johnson said: "Nothing is more important than the 3Rs and no government has done more to improve attainment in these basic skills."
He added: "The attainment of young people at the end of their primary years has vastly improved on what it was in 1997 and is higher than ever before for those reaching the end of compulsory education.
"The reforms that we have introduced are transforming education in this country and we are going further to ensure that every young person gets the best possible start in life."
The primary school test results seem to have reached something of a plateau after early gains.
Science - easily the strongest subject - showed the same level of attainment this year as in 2001.
The English result was at 75% for four years then rose to 78% in 2004 and has been on 79% for two years.
Maths has improved more consistently after slipping to 71% in 2001.
The figures were published by the Department for Education and Skills on the same day as the GCSE results came out.
This raised suspicions in some quarters, but the department said the date had been put in the diary by its statisticians.
'Out of steam'
Shadow education secretary David Willetts said 40% of pupils were still leaving primary school without having mastered the basic skills in the three Rs.
"This is letting down the nation's children who then spend their lives playing catch-up," he said.
"Moreover, the proportion of pupils achieving the expected level in reading, writing and maths has actually declined at age seven. The reading results at age 11 have also declined.
"This is clear evidence that the government's literacy strategy has run out of steam."