Almost a quarter of UK A-level entries were awarded the top grade this year, results published on Thursday show.
The proportion of entries given an A was 24.1%, up 1.3 on last year, said the Joint Council for Qualifications.
Amid continuing concern, ministers have already announced plans for changes to stretch the brightest and differentiate between the top performers.
The overall pass rate also rose: up 0.4 to 96.6%. There were markedly more entries for mathematics.
Girls outperformed boys in every major subject apart from modern foreign languages, according to the joint council (JCQ), which is the umbrella body for the main exam boards in England, Wales and Northern Ireland.
There was a record number of entries, 805,698 in all, 2.8% more than last year.
'Day of celebration'
JCQ director Ellie Johnson Searle said: "The hard work of students and teachers is clear, especially when judged against the continuing rigour and robustness of the assessment system in the UK.
The turnaround in mathematics - both in overall numbers and in achievement - is encouraging in the first year of the
So from next year, universities will see the grades for each of the six units that make up an A-level, as well as the overall final grade.
To provide more challenge, students are likely also be asked to produce an extended project, and to face tougher questions in their A-level papers - with perhaps an A* grade, as at GCSE level, to identify the highest achievement.
NI students did best
As usual, the Northern Ireland entries were the most successful in 2006: the pass rate was 97.7% and 32.4% were awarded A grades.
In Wales, 96.9% passed with 23.9% getting an A.
England did worst, relatively: 96.5% of entries passed and 23.8% achieved an A.
Too few students in Scotland take A-levels for the figures to be published separately.
Also published were the results at AS-level, which since the curriculum 2000 changes is the halfway stage towards a full A-level and a qualification in its own right.
The overall pass rate rose 0.2 to 87.5% and 18.4% were awarded A grades (up 0.5).
The difference between the AS an A-level success rates reflects how students tend to drop their weaker subjects as they go on to complete their two years of study.
League tables
Although candidates get their individual results on Thursday, the national figures relate to exam entries rather than candidates.
Provisional national statistics on how the students have performed, such as the proportion getting two or more A-levels and their average points scores, will not be available until October.
The national school and college "league tables" for England, based on the results, are not published until the New Year.
GCSE results are due to be published next week - on Tuesday for the Northern Ireland exam board, and on Thursday for all the boards.
First published on the BBC website|