Pupil:teacher ratios in state schools have risen for the sixth year running, according to the latest figures from the Department for Education and Employment.
These show that this year there is an average of 1.6 more pupils for every teacher in schools in England compared with 1990.
Average pupil:teacher ratios for local authority and grant-maintained schools rose from 18.3:1 last year to a provisional figure of 18.5:1. In 1990, there was an average of 16.9 pupils for every teacher.
The figures suggest funds are being switched from secondary schools, which lost 800 teachers in the last year, to primaries, which had 1,100 more, to cope with extra pupils.
A report by the Association of County Councils this week called for another 6,800 teachers, costing Pounds 174 million, to bring down the overall pupil:teacher ratio to 18:1.
This would be in addition to the extra staff needed to cope with rising pupil numbers, the association says.
The Liberal Democrats warned in the run-up to this week's local elections that 5,000 teaching jobs would go throughout England and Wales this year because of spending cuts. The estimate was based on a survey of 29 local authorities.
Education spokesman Don Foster said the amount of money the Government estimated was needed for schools in the standard spending assessment had fallen by 9.5 per cent in real terms since 1992.