By Gary Eason BBC News Online education editor

It appears the limited progress towards national targets is being sustained by a boom in vocational qualifications - each worth the equivalent of four higher-grade GCSEs.

Unpublished official figures obtained by BBC News Online show that 49.7% of pupils got five GCSEs at grades A* to C in 2003. Last year 50.2% did so.

These relate to GCSEs only - not the figures usually published by the government, which include the equivalent vocational exam results.

Those GNVQ results are not available separately at this time, the Department for Education has said.

But its published figures for GCSE and GNVQ results combined went up, albeit by less than ministers had hoped.

VOCATIONAL BOOM Each intermediate GNVQ is counted as four GCSEs at grades A* to C Results rise but targets missed More opt for work-related study Exams glossary

The Department for Education stressed that this year's figure was provisional and last year's was the final, revised figure - as with all the results it issues at this time.

The department has said it cannot provide the separate GNVQ figures yet "due to data quality issues".

But the raw results for GNVQ qualifications, issued by the joint exam boards in the summer, showed a huge rise in the number of intermediate full course GNVQs taken this year - up by 42%, to 94,017.

Those figures are for England, Wales and Northern Ireland, and neither the department nor the exam boards was able to give a breakdown on Wednesday, except to say that the vast majority were in England.

Earlier data show that in specialist technology colleges the proportion of the total GCSE/GNVQ points accounted for by GNVQs rose from 1.1% in 1998 to 4.5% last year.

In the department's normal published statistics, each intermediate GNVQ is counted as four GCSEs at grades A* to C. Part one GNVQs count as two GCSEs.

In those statistics, released on Wednesday, the department headlined the "GCSE/GNVQ results" but quickly slipped into talking about GCSEs only.

"The percentage of pupils receiving good grades at GCSE is improving - a one percentage point increase to 52.6% of pupils gaining five or more grades A*-C," it said - meaning "or their GNVQ equivalents".

Nowhere in the mass of statistics on student achievement produced each year does the department give the GCSE-only figures.

'Fairer'

The general secretary of the Secondary Heads Association, John Dunford, agreed with the analysis that it must be the boom in vocational qualifications that was sustaining the overall rise.

It was not necessarily a surprise that the GCSE success rate had fallen, he said.

"When the results came out in the summer there was a decrease in subjects like business studies and a big increase in the GNVQ courses.

"So it's almost certainly people being entered for GNVQ courses who in previous years would have been entered for GCSEs."

But he said the inclusion of GNVQs in the official statistics gave a fairer picture of the achievement of 16 year olds.

"It demonstrates why schools are so keen for the Tomlinson Committee [appointed by the government to look at 14 to 19 education] to come up with a better menu of vocational qualifications to appeal to those who are not achieving anything under the current system."

Shadow Education Secretary Damian Green said the figures were "worryingly misleading".

"It's an alarming trend. The covering up of facts and figures seems to be the norm these days."

Welsh discrepancy

In Wales, there is also a gap between the GCSE/GNVQ attainment and the GCSEs alone.

The Welsh Assembly said at the end of last month that 51% of 15 year olds had achieved five or more GCSE grades A*-C.

But this included the vocational equivalents.

In fact, the figure for the top GCSE grades alone was 50% - the same as in 2002.

The apparent increase of one percentage point over last year was not in the GCSE results.

Call for review

Professor Alan Smithers of the University of Liverpool said it was time the Department for Education reviewed the GNVQ's equivalence with four GCSEs.

That had come about for historical reasons, when a GNVQ was envisaged as a whole programme of post-16 study leading to a particular career.

"It's an easy route to four GCSEs," he said.

"It may be a very successful course and it may be the best way of teaching information technology, but it's like getting eight euros to the pound - the exchange rate hasn't been worked out properly."

He said young people's education was being distorted by the need for the department to meet targets set for it by the Treasury.

"I hope the DfES will look at the equivalences. If it were made equivalent to perhaps one or two GCSEs, then it would be taken up on its merits rather than as a way of meeting the targets."