A former Fás tutor who was at the centre of its recent marking scandal claims he has been the victim of a "witch-hunt" by the state agency in an attempt to mask wider problems with its courses.

Darren Louet-Feisser, who now runs a product design company and has appeared on the popular TV programme Dragons' Den, claims he was allowed to teach a Fás course in Computer Aided Design (CAD) in Cavan during 2006 despite not having the required training certification.

Speaking publicly for the first time about his involvement in the controversy, he said he had "held his hands up" when contacted by Fás about the problems with the exams, and had acknowledged that he incorrectly allowed students to pass the course.

However, he claims the problems were due in no small part to the fact that he was provided with little or no guidance on how to correct exams, and was led to believe that the exams themselves were not important and were merely "a formality".

Details of Louet-Feisser's failure to mark the exams properly prompted a wider Fás inquiry into standards of teaching which identified other serious issues

"I have loads of hands-on experience in design. I've worked all over the world. I genuinely thought my students had passed, but I acknowledge that the exams were not done properly by me. But I was given no guidelines on how to correct them," he told the Sunday Tribune.

Now Louet-Feisser says he is concerned that the negative publicity surrounding his time teaching the course will affect his attempts to move on with his life with his new company, Louet Woods Products Ltd. The company was offered investment on Dragons' Den. While Louet-Feisser and his partner have since turned this down, he said he found the experience extremely rewarding and still keeps in touch with the business mentors on the show.

"Three years ago, just after this, I picked myself up and started my own company. We're a legitimate business with international customers. This sort of stuff is just trying to destroy my name and integrity," he said. "I didn't realise I was doing anything wrong. When Fás said 'you corrected the exams wrong', I held my hands up and said okay. I was fired, but I thought that would be the end of it."

Asked to comment on Louet-Feisser's claims, a spokeswoman for Fás noted that he was employed by an external company, not by Fás directly.

"It is the responsibility of the contractor to ensure that the service provided meets the requirements of Fás," she said. "Fás does assess for compliance on all its training programmes on completion of training and prior to applying for certificates from awarding bodies. In this case it is important to note that no certificates were issued to learners on this course. Fás officials were not satisfied with the assessment and exam materials. An internal audit examination followed and corrective action was taken."