Business leaders will criticise the Government's diplomas today, saying that they are in danger of splintering independent and state schools.

Richard Lambert, director-general of the CBI, was initially a keen supporter of the diploma, which was established to end the divide between theoretical and practical qualifications.

However, in a dramatic split from the Government, he criticised the most recent diplomas in languages, humanities and science, describing them as an “unnecessary distraction”. These academic subjects are a departure from the first 14 work-based diplomas.

When announced last October, the three latest disciplines were regarded as a way of ensuring the success of the diploma, by appealing to universities and appeasing parents unhappy at the thought of their children studying for a vocational qualification.

A review of sixth-form qualifications will take place in 2013 and the Government has refused to guarantee the future of A levels beyond then.

A spokesman said: “The CBI is urging the Government to think again about its over-ambitious plans for a new wave of academic diplomas, and concentrate on making sure GCSEs and A levels give young people the skills and knowledge to succeed.

“Going ahead with these plans without tackling concerns, employers fear, could lead to a fractured two-tier education system with private schools opting for GCSEs and A levels while state schools use diplomas.”

The spokesman added: “Employers have consistently backed the Government’s sector related diplomas as a parallel qualification to GCSEs and A-levels. They were created with substantial business input and retain the strong support of employers.

“However, employers are worried about the more recent proposals in the Government’s diploma strategy to introduce a new range of academic diplomas in humanities, languages and sciences.

“CBI members fear they would not have any greater value to young people or to employers than the existing GCSEs or A-levels, and would instead be an unnecessary distraction.”

The CBI also said ministers should streamline the diploma, which could eventually be taken at seven levels in 17 subjects. Pupils will need to travel between different schools, colleges and businesses for lessons and work experience.

The spokesman added: “There are concerns that the over-loaded education system could not cope with all the planned reforms given the lack of resources available, including too few specialist teachers in maths and science, and a poor careers advice service.

“Over the next few years, schools and colleges are already being expected to manage a raft of changes.

Ed Balls, the Schools Secretary, said the diploma, which will be offered in numerous permutations to 14 to 19-year-olds from this September, could become the “jewel in the crown” of the education system.

Mr Lambert said: “There has been genuine enthusiasm for the sector-specific, vocational diplomas. Introducing a range of science, humanities or languages diplomas runs the risk of undermining the integrity of traditional academic subjects.”

Jim Knight, the Schools Minister, said the CBI was part of the expert group that approved the diplomas.

He said: “I am surprised at this negative response from the CBI on our three subject-based Diplomas, given that Richard Lambert shared the platform with Ed Balls and myself when we launched them last October.

“I believe the unique mixture of theory and applied knowledge the Diploma offers will help boost the number of young people studying science and languages, by bringing these subjects to life and giving students the skills employers want.”

Michael Gove, the Shadow Schools Secretary, said: “By pushing ahead with plans for academic diplomas the Government risks undermining the existing diploma and they are threatening the future of both GCSEs and A levels.

“Ministers are pressing ahead with this proposal for purely partisan reasons and are putting ideology ahead of the needs of students and the economy.”

However, the CBI believes academic diplomas are neither fish nor fowl. It says the Government should drop such qualifications, and instead focus on improving A-levels and GCSEs, which should remain the “cornerstone” of education.

This change of opinion came after extensive consultation with businesses across the country.

Christine Blower, acting general secretary of the National Union of Teachers, called the CBI’s attack on diplomas “untimely” and said its aim to separate young people on to vocational and academic routes was “profoundly pessimistic”.

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