The clamour for state schools to teach International GCSEs was dealt a blow yesterday when the Government’s curriculum advisers came out against the exams. The Qualifications and Curriculum Authority said the IGCSEs failed to assess the whole curriculum at key stage 4, implying the tests did not provide assurance that all areas of study had been covered.

In a scathing report comparing the alternative exams - they are now offered by around 200 private schools - with their conventional counterparts in four subjects, QCA criticised IGCSEs for:

* Failing with English to include any compulsory Shakespeare, mandatory assessment of speaking and listening, or compulsory drama study.

* Not including in French speaking tests in part of the exams.

* Allowing calculators for maths in all sections of the exam. Conventional GCSEs include compulsory non-calculator papers.

* Placing less emphasis in science on investigative practical methods and for not requiring students to learn about how scientific ideas developed.

Private schools backing the exams say the international exams are more rigorous than GCSEs, which had become “too easy” for many students. But the report said English IGCSEs were easier than the “highly demanding” GCSEs, partly because of the flexibility over Shakespeare. In other subjects, at least one version of the IGCSE was found to be harder. Cambridge Assessment, which offers IGCSEs, said the regulator could not fairly make judgements on the relative difficulty of the rival exams, since it had not looked at candidates’ scripts or mark boundaries. The report may be a setback to Lord Adonis, the schools minister, who last month appeared to be paving the way for state schools to offer the IGCSE. He announced plans to consult on allowing state schools to teach the exams and including them in league tables.

This began yesterday and will conclude early next year. The QCA’s report makes it less likely that it will accredit the IGCSE. Technically, the IGCSE could still be allowed in state schools without QCA accreditation, if the Government chose this option.

Cambridge Assessment, which argues state pupils should have access to a broad range exams, said consultation would allow a wider evaluation of the IGCSE’s merits. Edexcel said recent Government moves to cut coursework from many GCSEs lessened the need for an alternative.

HOW THE EXAMS DIFFER

English

GCSE:Compulsory speaking and listening (20%); reading (40%); writing (40%).

Pupils required to study Shakespeare play, work from prescribed list of authors; non-fiction and media texts. Compulsory coursework: 20%.

Difficulty level: GCSE more demanding (more content). Assessment: up to four hours, plus coursework.

IGCSE:Speaking and listening: not part of main exam in Cambridge International (CIE) version; part of optional coursework with Edexcel.

No requirement to study Shakespeare. Exams mainly assess unseen text (CIE) and unseen text and from anthology (Edexcel).

Coursework: Optional. Counts as 50% (CIE); 20% (Edexcel).

Difficulty level: Less demanding (less specified content). Assessment time: Up to 3.75 hours (exam only), or up to two hours plus coursework.

Maths

GCSE:80% exams, 20% compulsory coursework (10% using and applying maths; 10% handling data).

Calculators barred from one of the two papers. Formula sheets given.

Difficulty level: Comparable, though Cambridge IGCSE harder at foundation level.

Assessment time: Foundation tier: three hours. Higher tier: four hours.

IGCSE:Optional coursework in addition to compulsory exam papers (CIE); no coursework (Edexcel). Calculators allowed in all papers.

Formula sheets not given (CIE); given(Edexcel). Difficulty level: Comparable, though CIE’s IGCSE harder at foundation level.