Boys' writing standards have fallen in the past year with only 55 per cent reaching the level expected of them, national curriculum test results for 600,000 11-year-olds show.

David Hart, general secretary of the National Association of Head Teachers, said they showed there was "one hell of a lot to do" to improve boys' writing skills. He blamed the slide - the percentage reaching the required standard fell one percentage point this year putting them 17 points behind girls - on a culture among boys "that says it's cool not to learn ".

The drop in writing standards among boys was, though, the only major downside in figures which otherwise showed a one percentage point rise in the proportion reaching the required standard in maths and English.

The rise meant ministers have finally reached the target of 75 per cent set for maths in 2002. However, they are still tantalisingly one percentage point short of the English target of 80 per cent. It was clear, though, that the Government has virtually no hope of reaching the "aspiration" set for 2006 - of 85 per cent in both.

The drop in writing standards - coming after a year in which the boys' performance went up by five percentage points - was a major surprise.

It coincided with an improvement in their performance in the reading test where the figure was up from 79 per cent to 82 per cent - thus narrowing the gap between them and girls from eight percentage points to five.

In maths, boys outperformed girls with 76 per cent reaching the standard compared with 75 per cent.

"While it is good to see boys' reading improve, the yawning gap between boys' and girls' writing skills needs to be closed, and quickly," said Mr Hart. "Primary schools are having to tackle an attitude among boys which basically says that it's not cool to learn."

Jacqui Smith, the Schools minister, welcomed the results. "More 11-year-olds than ever before are reaching the required standard in maths and English," she said. A breakdown of the figures showed that 120 of England's 150 local education authorities now had 75 per cent of youngsters reaching the required standard in English - compared with just four in 1998. Put another way, it meant about 96,000 more 11-year-olds were leaving primary school achieving the expected level for their age in English and 84,000 in maths.

Yesterday's results follow the publication of research by the Association of Teachers and Lecturers claiming that ministers' claims of a rise in standards as a result of improved test results were exaggerated. The research, by Professor Colin Richards, a former specialist adviser on primary education to Ofsted - the education standards watchdog - claimed part of the rise was due to teachers teaching to the test and therefore it was not sustainable into secondary schooling. He also disclosed that teachers' own assessment of their pupils' performance was that their standards had not risen as dramatically as test results suggested. Yesterday's results underlined this trend in English with teacher assessments showing 75 per cent had reached the required standard compared with 79 per cent.

Ms Smith insisted the results showed there had been an improvement in standards. "I think today should be about celebrating the success of our primary schools, their teachers and pupils," she said.

The results showed the proportion reaching the required standard in science remained at 86 per cent.

Seven-year-olds had also shown a modest improvement in maths and English - with 85 per cent reaching the standard in reading, 82 per cent in writing and 91 per cent in maths, all up one point. Science remained at 90 per cent. Meanwhile, pupils in Northern Ireland achieved record GCSE results with the overall pass rate rising by 0.6 per cent to 90.8 per cent. The percentage of A* to C-grade passes also rose by 0.9 per cent to 70.5 per cent. Pupils in England and Wales get their results tomorrow.

The pass rates

% 2004/2005

ELEVEN-YEAR-OLDS

ENGLISH

Boys 72/74

Girls 83/84

Combined 78/79

READING

Boys 79/82

Girls 87/87

Combined 83/84

WRITING

Boys 56/55

Girls 71/72

Combined 63/63

MATHS

Boys 74/76

Girls 74/75

Combined 74/75

SCIENCE

Boys 86/86

Girls 86/87

Combined 86/86

SEVEN-YEAR-OLDS *

READING

Boys 80/81

Girls 87/89

Combined 84/85

WRITING

Boys 76/77

Girls 87/88

Combined 81/82

MATHS

Boys 89/90

Girls 92/92

Combined 90/91

SCIENCE

Boys 88/88

Girls 91/91

Combined 88/90

* 2005 is first year schools have reported results of teacher assessments of seven-year-olds rather than tests.