The number of infants - five-to-seven-year-olds - in classes over 30 increased by 8,000, to 484,000. The Government pledged at the election to cut that to nil by 2002.
Yesterday Stephen Byers, the school standards minister, insisted that the Government was on course to meet its target as early as 2001.
"We can guarantee to parents that this is the final chapter in the saga of ever-increasing infant class sizes. The book is now closed on infant classes being more a question of crowd control than a valuable learning experience," he said. "We have already made substantial moves to make a flying start from September with pounds 62m in this first year alone."
The increase, coming on top of Thursday's announcement of increased NHS waiting lists, is a blow to the Government. But ministers blamed the rise on the legacy of the last government's local authority spending limits.
Mr Byers said the extra money would pay for 1,500 new teachers from September to take 100,000 children out of large classes. Another pounds 40m would build 600 classrooms. Phasing out the Assisted Places Scheme would eventually yield pounds 100m a year, government sources said.
Angela Browning, the Tories' education spokesperson, said the Government was "going backwards" and accused ministers of duplicity. "Nearly half of all county councils, and a quarter of big-city councils, expect class sizes to increase further in the next 12 months," she claimed.
Don Foster, the Liberal Democrats' education spokesman, said: "Unless the Government takes urgent action ... another of Labour's early pledges will bite the dust."
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said the figures meant "the bullet of parental choice has to be bitten. Within realistic financial resources, unfettered parental choice is irreconcilable with keeping classes to a maximum of 30."
On average, classes for five-to-seven-year-olds increased in size to 27.1, up from 26.9 a year earlier. The overall average for primary schools increased from 27.5 to 27.7.
The average size of secondary classes, including sixth forms, remained at21.7. But class size for pupils of 11-16 rose from 23.4 to 23.6.
The figures also provided fresh evidence of the crisis in teacher recruitment. Teacher vacancies in schools rose from 1,814 in January 1997 to 2,359 this year.Reuse content