Students hoping to study science at Cambridge University in the future will need to score higher grades in their A-levels.
The prestigious institution has upped its standard entry offer so that from 2015, anyone aiming to take a science-based degree will need at least two A*s and an A at A-level or equivalent.
The current offer is one A* and two A grades and this will remain for arts subjects, the university said.
Cambridge insisted that the change is not raising the bar for would-be students, with more than nine in 10 (92%) successful science applicants already achieving two A* and one A, or better at A-level. The majority of these students were educated in state schools.
In a statement, the institution said: "The university believes that the revised offer gives applicants a clearer indication of the level of attainment realistically required to compete for a place, and to thrive on science courses."
It added: "The university will continue to make non-standard offers where appropriate, based on consideration of relevant contextual data including any extenuating circumstances which may have adversely affected an applicant's academic attainment."
The A* grade was first awarded in the summer of 2010 as part of a bid to distinguish between the best students.
To receive the grade, students must score at least 90% on their papers in the second year of their course, as well as obtaining an A overall.
Figures published last summer show that 7.6% of exams were awarded an A* in 2013 compared with 7.9% in 2012.