Estelle Morris seems to be on the back foot and swinging wildly

Patricia Metham, Roedean School

But Patricia Metham, head at Roedean School in East Sussex, has criticised the introduction of the distinction grade as likely to add further worries to pupils already facing the stresses of achieving an A grade.

It will mean more "demoralised pupils" who will feel that they have failed to reach the top grade - and will "add to the pressures on young people", she said.

Nobody, apart from 10, Downing Street, seems to want it. It sends totally the wrong message to bright students who fail to achieve a distinction.... It will deter good students from aiming for the best universities

Graham Hart, National Association of Head Teachers

This is not a reform driven by educational need, she says, but is a "knee-jerk" reaction to a political agenda.

"Estelle Morris [the education secretary] seems to be on the back foot and swinging wildly," said the head of the girls' boarding school.

Opposition to the distinction grade was also voiced by a head teachers' union leader, who said that it was "totally unwarranted".

"Nobody, apart from 10, Downing Street, seems to want it. It sends totally the wrong message to bright students who fail to achieve a distinction.... It will deter good students from aiming for the best universities," said David Hart, leader of the National Association of Head Teachers.

Her pupils were able and gifted, but also very competitive, she said, and this grade for the top 2% to 4% would mean more anxiety in the exam season.

'Moving the goalposts'

"It adds a complication which schools could do without at this time," she says. And she questions the destabilising impact of "moving the goalposts again".

And in practice, the insertion of a new grade will mean that it will devalue grades lower down the scale.

When Ms Metham talked to her pupils about the proposals, she found that they were also sceptical about the practicalities of the new grades.

If there were additional questions, would there be extra time allowed? And if there were separate questions, would pupils have to gamble on whether to take the distinction grade questions?

If the intention of the new grade was to help universities identify the most gifted pupils, Ms Metham said there were other ways this could be achieved.

Universities had their own assessment procedures, she suggested, and if exam results were to be more precisely defined, percentages could be used, without having to further confuse the exam system.

The real pressure to introduce another grade was from politicians, she suggested, who wanted to defend themselves against accusations of exams getting easier.

Although she says that in practice A-levels are now so different from a generation ago that it is "not comparing like with like".

"We would not award the secretary of state a distinction, advanced or otherwise, on what we have heard so far," said the head teacher.