The latest figures on class sizes in England, published by the Department for Education on Wednesday, show that the number of five, six and seven year olds in overcrowded classes has continued to fall.

Infants in over-sized classes

January 1998: 485,000 January 1999: 356,000 January 2000: 177,000 September 2000 (forecast): 50,000

And class sizes for older primary pupils are beginning to fall - with the average decreasing from 28.4 to 28.3 pupils per class.

The Shadow Education Secretary Theresa May accused the government of chasing "political targets" rather than supporting schools and of "conveniently ignoring" that secondary school class sizes were increasing.

The increase in secondary class sizes was attacked by the general secretary of the Secondary Heads Association, John Dunford, as evidence that progress in primary schools was being achieved at the expense of under-funding in secondary schools.

Calls to cut class sizes for junior and secondary classes were also made by the general secretary of the National Association of Head Teachers, David Hart, who called on the government to "give heads the additional cash they need".

There are now 177,000 pupils in infant classes with more than 30 pupils - compared to 356,000 in January 1999.

And Mr Blunkett forecast that this figure will have fallen to 50,000 by September 2000, putting the government ahead of schedule to reach its election target of no infants in classes of over 30 pupils by 2002.

David Blunkett: Junior class sizes falling

"This means that since the election, 300,000 children who would otherwise have been in large infant classes have now benefited," said Mr Blunkett.

"And the figures give the lie to the claim that lower infant class sizes are 'at the expense' of older pupils."

Junior target

But the education secretary admitted class sizes in secondary schools were getting worse - with average class sizes rising from 22 to 22.2 pupils per class.

"I predicted before Christmas that there would be a slight worsening of the class size position in secondary schools ... but I want to take my critics on in that because they can't have it both ways.

"Either they want us to ring fence ear-marked money and say 'you can only spend it on class size' or they want the freedom to spend it in the school on raising standards."

And Mr Blunkett said that extra money for schools announced in the Budget could be spent by secondary head teachers on recruiting teachers to cut class sizes, he said.

The National Union of Teachers welcomed the setting of class-size limits for infants, but said there were still far too many older pupils in classes with more than 30 pupils.

Parental choice

Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said a decline in pupil population was the chief reason for the fall in infant class sizes.

He welcomed the reduction, but said he would have preferred to see a "sensible policy" governing parental choice.

This would mean that when class sizes reached 30, parents would have to send their children to other schools, rather than popular schools expanding to accommodate more pupils.

The government would be better off using the more than �600m spent on cutting class sizes to increase teachers' salaries, buy more books and equipment, and create more pupil referral units, he said.

Reducing class sizes was one of the key pledges set by Labour ahead of their landslide victory three years ago - with the promise to achieve smaller class sizes by 2002 later revised to September 2001.

The statistics on class sizes have been angrily disputed, with the government focusing on the achievements within its target age group - and the opposition claiming this disguises an overall rise in class sizes.

Last year's official figures showed that class sizes for infants were falling sharply. When the present government took office there were almost half a million five to seven-year-olds in classes of 31 or more pupils.