A qualification that Ofsted has warned is of "doubtful value" has become the fourth most popular 14-19 course in English schools, The TES has learned.
A 669 per cent rise in entries in the last two years means the OCR National level 2 in ICT has been used in more than half of secondaries and is now being taken by more pupils than many GCSEs in maths, English and science.
In March the schools watchdog said the course taught pupils what they already knew, neglected essential skills and was causing a sharp decline in ICT post-16.
But Greg Watson, chief executive of the OCR exam board said this week that the verdict was "subjective". "When we asked Ofsted to give us evidence for statements like that, there was very little," he said.
The qualification was only introduced in 2004 but had 242,878 registrations last summer, which meant only AQA's English and English literature GCSEs and Edexcel's maths GCSE were more popular.
Mr Watson said he expected the growth to continue because teachers enjoyed teaching OCR Nationals and pupils found them "motivating, very relevant and very clear in explaining what is expected and what they are trying to achieve".
But other critics have described the ICT level 2 National as a "tick-box" course. In 2007 The TES revealed that consultants from the Government's National Strategies had found the standards needed for a pass were generally equivalent to those expected of the average 11-year-old.
The longest version is deemed equivalent to four good GCSEs for league tables despite needing around half the teaching time and some schools are believed to simply be using the qualification to boost their table positions.
OCR denies this, arguing that schools are offering it to compliment GCSEs in other subjects and pointing out that only one in seven Nationals are awarded in the four GCSE version.
But the board's own papers show that all versions of the ICT level 2 National involve considerably less teaching time, whatever number of GCSEs they are deemed equivalent to.
Asked whether he thought entries would drop under the Conservatives' plan to bar vocational qualifications from the main school league tables, Mr Watson said: "I don't think so and I hope not.
"Schools' main driver should be to provide the right sort of qualification for each individual learner and the incredibly positive feedback we have shows teachers value the Nationals in that sense."
The board offers the vocational qualifications in nine subjects. But the popularity of ICT dwarves the rest, accounting for 83 per cent of all OCR National entries.
Ofsted's report did not name the ICT vocational courses it criticised. But The TES understands the authors were worried about the OCR National and Edexcel's Diploma in Digital Applications, with particular concerns about the OCR course.
Opinion was split on the TES Forums. A grammar school teacher said the OCR National was "the most engaging ICT course currently available". But another contributor described it as "soul destroying".