Pupils could face seven exams before their GCSEs

Instead of taking "key stage" tests at three fixed points, pupils would sit shorter but more frequent exams in English and maths.

Education Secretary Alan Johnson likened them to musical instrument exams, in which children move up a ladder of eight grades at their own pace.

He said: "We think that good tracking by teachers, confirmed by shorter, more frequent tests, will help schools to personalise each child's learning.

"This will motivate all pupils to move on and up by recognising what they have achieved and showing them where they have to go next - just as a child who passes their Grade One on the recorder feels excited to move on to playing harder tunes."

But the prospect of an increase in exams fuelled growing concerns that youngsters are being deprived of their childhoods by over-testing.

Many face taking twice as many exams as they do now.

The changes are being tested in nearly 500 schools for two years from September.

They would spell the end of the traditional key stage testing regime in which pupils are assessed at the ages of seven, 11 and 14.

However, arrangements for science would be unchanged, with pupils tested on the subject at the end of key stages.

The new system has come about because ministers are concerned the current arrangements are not pushing up standards fast enough.

Improvements have levelled off in recent years, leaving the Government failing to meet many key education targets.

Aides to the Education Secretary also said the proposed system was intended to be fairer.

Children would be able to take "progress tests" whenever their teachers thought they were ready - stretching the brightest and preventing the weakest falling behind.

Pupils would have two chances a year to take a test - in December and spring.

They can take the first two "grades" at the same time, and would then move up one level at a time.

But there were warnings last night that youngsters risk burnout on an "exams treadmill" before they even start GCSEs and A-levels.

Tony Roberts, a leading member of the National Association of Head Teachers, said: "That these tests are to be externally marked is absolutely ludicrous.

"It is going to put more pressure on teachers but the bigger concern is there will be even more pressure on children to perform in tests.

"There are already increasing concerns children do not spend enough time on constructive play and are not allowed to do the sort of things most of us did."

The other changes would see 21,500 pupils in the pilot group who have fallen behind their classmates in English benefiting from ten hours of extra one-to-one tuition at home or in a local college.

A further 21,500 will get personal lessons in maths. Heads will be handed cash bonuses called "progression premiums" if they can demonstrate they are driving up standards.

League tables are also likely to be reformed to show measures of progress made alongside headline results.

The Department for Education and Skills yesterday called on teachers to create an atmosphere in which it is trendy to work hard and "boffins" are not bullied for being too brainy.