Teachers will be required to offer mortgage-style impartial advice on the courses available to their pupils and "must not unduly promote any particular options".

The proposals follow speculation that A-levels could be abolished after ministers refused to guarantee a future for the traditional exams.

The Education and Skills Bill, to be debated in Parliament on Monday, contains a clause intended to force schools to give teenagers objective advice. The move is designed to stop teachers attempting to recruit pupils onto sixth-form courses simply as a way of boosting school funding.

Under the Bill, schools will have a new duty to provide "impartial" advice to "promote the best interests of the pupils concerned".

Schools and colleges must not "seek to promote, contrary to the pupils' best interests, the interests or aspirations of the school or of other persons or institutions". The material provided to pupils must present them the full range of options and "must not unduly promote any particular options over any others".

Maggie Scott, director of learning at the Association of Colleges, said the clause was "great news for young learners who deserve impartial, comprehensive expert advice and guidance".

"Many people in Britain think that the careers advice they received at school just wasn't up to the job. In our latest survey over half of all adults said that they would chose a different course of study if they had another chance, and that if they could now access independent careers advice and guidance they would use it."

A spokeswoman for the Department for Children, Schools and Families said the Government wanted pupils to have advice on the range of different options available. Those include diplomas, apprenticeships and the International Baccalaureate as well as GCSEs and A-Levels.

"It is not about promoting one option over another, since it is up to individual pupils to decide the best route for themselves, in discussion with their parents and teachers," she said.