Pupils will need to be paid to take the "English Baccalaureate" if ministers want their proposed new qualification to work, the head of one of England's biggest exam boards has warned.
Simon Lebus, Cambridge Assessment chief executive, believes "an appeal to young people's pockets" is required to ensure widespread take up of the "Bac" - a balanced mix of five academic GCSEs.
He has suggested pupils could be financially rewarded once they had passed the new qualification, possibly through discounts on interest rates for university tuition fee loans.
Heads' leaders say the idea is "dangerous" and that pupils should be encouraged to value education for its own sake.
But speaking at a conference organised by Cambridge Assessment - which runs the OCR A-level and GCSE board - Mr Lebus said: "If the commendable concept of an English Bac is to succeed I think we probably need to consider an appeal to young peoples' pockets as well as their educational aspirations.
"This is not, of course, very idealistic, but reflects, I think, that combination of realism and clear-headedness that is an essential ingredient of successful assessment reform."
Education Secretary Michael Gove suggested an "English Bac" last month to encourage pupils to take a wider range of academic GCSEs.
It would require them to gain five "good" GCSEs, including "English, maths, a science, a modern or ancient language and a humanity like history or geography, art or music".
Mr Lebus said: "The problem is that taking a group of existing qualifications and putting an envelope around it doesn't in itself encourage take-up."
His concerns are partly driven by the experience of the Diploma, which has had lower than expected take-up despite heavy promotion under the previous government.
"With the experience of Diplomas still fresh in our minds, we can see how difficult it can be for major assessment reforms to succeed, even with all the apparatus of state behind them," Mr Lebus told the conference.
He declined to say how much he thought pupils should be paid but said that the money should come from Government.
Brian Lightman, Association of School and College Leaders general secretary, said: "We shouldn't be paying pupils to provide an incentive for them to gain qualifications they need. We should value education for its own sake. This would be a dangerous road to go down."
Mr Lebus welcomed the Government's call for greater university involvement but said it would require extra funding.
This was needed urgently or else "we may find that we end up inadvertently and expensively drifting into a continental system of four-year degrees", he said. He also called on ministers to end the practice of "recklessly" introducing changes to the assessment system without trials.
The Department for Education declined to comment.