In some areas fewer than half of eligible students receive an education maintenance allowance, intended to encourage 16 to 19-year-olds from low-income backgrounds to continue in education.

Last week the Government announced that it would introduce a similar pound;30 per week grant for adult learners as part of its skills White Paper.

Chancellor Gordon Brown said the four-year pilot of EMAs had proved a success, helping 20,000 extra students a year to stay on in education.

But figures revealed by Ivan Lewis, junior education minister, in response to a parliamentary question by Phil Willis, Liberal Democrat education spokesman, show that three in 10 eligible 16 to 19-year-olds do not claim their money.

Currently EMAs are restricted to 56 pilot areas but will be extended nationwide from September 2004.

In Suffolk, fewer than one in four eligible teenagers claims the grant, in Lancashire East 48 per cent and Wakefield 51.

By contrast, almost all eligible students in Stoke-on-Trent and the London boroughs of Hackney, Tower Hamlets and Newham receive their money.

Mr Lewis warned that the figures “carry some degree of uncertainty” because estimates of the number of eligible students are based on 1991 census data.

Mr Willis said that the figures showed real problems with the EMA scheme. “The whole thing has been incredibly badly sold. This is not the universal panacea to improve staying-on rates that the Government would like it to be.”

A spokeswoman for the Department for Education and Skills said: “We are developing plans for national promotion to ensure that young people who could benefit know about the national EMA.”