ExamSupport. ie offers "revision packs" containing video lectures from a range of teachers. TUI general secretary Jim Dorney warns that prospective users should "be aware that there is no guarantee as to the quality of the information offered". Each pack costs 18.75, and a typical subject would contain around 15 different packs, addressing various topics within the subject's syllabus.

ExamSupport has defended its service, arguing that it is "not trying to undermine learning in school. What we're offering is more detail. We're not in any way a replacement for good structured learning in a class, " a spokesman said.

ExamSupport, which trades as part of Clear Voice Systems Ltd, went online about six weeks ago, but the site was only launched last week. Each revision pack contains a video lecture . . . on average about half an hour long . . .

and past-paper notes and model answers. Students can also download the audio of the electronic lectures on to an mp3 player, "and learn on the way to school", according to John McDonnell, director of sales and marketing for ExamSupport.

McDonnell sees the service as "complementary to classroom work" and believes the price is reasonable, despite the cost of an entire subject's revision packs coming to approximately 280. "E-learning from real teachers is the most intuitive form possible, " he says.

So far sales have been evenly spread around Ireland, although, McDonnell says, "there have been a lot in south Dublin for some reason. It's more a mindset that's probably more prevalent in Dublin . . . that extra tuition is acceptable and advisable." Most students buy one or two 'packs' and then return to buy five with a discount of 10%. "Fifteen [packs] is a subject, so I'd like to see them come back and buy 15, " McDonnell said.

The website is "not a replacement for actual classwork", the TUI says. "Students should always exercise due caution and only ever utilise such services as a supplement. . . They should also be aware that there is no magic solution to success in exams."