The Pre-U exam will compete with A-levels and Diplomas
Another alternative to A-levels, aimed at preparing students for university study, has been approved by the exams watchdog.
The Cambridge "Pre-U", intended to offer more "stretch and challenge", has been accredited by the Qualifications and Curriculum Authority.
The two-year courses will compete with A-levels and the forthcoming Diploma.
The exam board says the Pre-U will promote the "independent study skills that are required by universities".
The green light from the exams watchdog means that the Pre-U will be able to take its place in the qualifications structure - with one Pre-U officially worth one A-level.
In an increasingly crowded marketplace in courses for 16 year olds, the Pre-U will be seen as serving the more academically-ambitious schools, aiming to send pupils to leading universities.
Developed by the Cambridge International Examinations (CIE), the Pre-U has been likened to a more "traditional A-level".
It does not have a modular structure and emphasises the virtues of "digging deeper" into a subject - with exams at the end of two years of study.
It will also be seen as a way of helping oversubscribed universities to distinguish between the growing number of pupils who achieve A grades at A-level.
Last year, about one in four of the A-levels awarded were A grades - with independent schools achieving almost twice that level.
There have already been calls from independent schools for more rigorous A-levels.
The head of Harrow School has warned that unless the A-level is "strengthened" the school could switch to the Pre-U exam.
Head teachers have already warned about the risk of confusion and logistical complications when A-levels and Diplomas are both expected to be taught by schools.