Mike Tomlinson has sought to build a consensus for his plans

GCSEs, A-levels and vocational qualifications should evolve over the next decade into a new diploma system, the Tomlinson report recommends.

But there are signs the proposals will not have a political consensus.

The Conservatives say they would go back to having a fixed quota of A-level students getting the top grade, and keep external exams at the age of 16.

Basic skills

Under the Tomlinson plans, there would be fewer exams but, at advanced level, tougher questions would stretch the brightest.

There would be clearer routes for those wanting more specialised, work-related learning within the diploma.

KEY PROPOSALS Four-level diploma to be introduced as new qualification A-level and GCSE courses would be components Pupils learn at own pace, take exams when ready Vocational options improved Mandatory basic English and maths Recognition for other experiences, such as voluntary work Coursework replaced by a single big project Changes gradual - taking perhaps a decade More details

And everyone would have to have the "core" communication and numeracy skills businesses say children often lack.

The changes, taking up to 10 years to implement if adopted by the government, were recommended by the working party on 14 to 19 learning headed by Mike Tomlinson, former chief inspector of England's schools.

The advanced diploma exams would include extra questions to challenge those at higher ability levels.

These would offer new A+ and A++ grades on top of the present A grade.

But the Conservatives dropped something of a bombshell on Sunday by saying they would turn back the clock to the system that used to exist until the early 1980s.

This would mean only a fixed proportion of students, perhaps 5% or 10%, could get a top grade, however well the others did against an objective standard.

NEW DIPLOMA - CURRENT EQUIVALENTS Advanced - AS-level and A-level, Level 3 NVQ, BTec Nationals and others Intermediate - GCSEs grades A* to C, Intermediate GNVQ, Level 2 NVQ and others Foundation - GCSEs grades D to G, Level 1 NVQ and others Entry level - Entry level certificates

At intermediate level, roughly equivalent to the current GCSEs, the Tomlinson ideas are likely to involve a far greater reliance on internal assessment by teachers.

But classroom teachers' unions have expressed concern that their members' workloads might increase.

And Conservative spokesman Tim Collins said his party wanted to keep external assessment.

Employers also remain sceptical about the Tomlinson proposals.

Others have welcomed them, however.

"What I want from the government is strong support for the Tomlinson report - I don't want any fudge," said David Hart, general secretary of the National Association of Head Teachers.