The man who investigated this year's A-level grading problems has said there can be no guarantee that there will not be trouble next year.

But Mike Tomlinson, the former chief inspector of England's schools, said he believed the system was now secure, so there could not be the same problems again.

Answering users' questions in a BBC News Online interactive forum, Mr Tomlinson said he had now been asked to look at the next exams and would be "looking very sharply at what happens and reporting very publicly" if things did not operate properly.

Mr Tomlinson was asked in September to investigate complaints by schools about their students' exam results being downgraded.

As a result of his review, some 9,800 students' unit grades were increased, the knock-on effect being to raise an overall A-level grade for about 1,200 of them.

No repeat

Mr Tomlinson said the problems had involved a failure to define the standards required of candidates, compounded by a code of practice which gave exam board chief executives too much freedom, and a lack of training.

"Those things have been tackled, very much so, and are going to be in place by the end of this calendar year.

"So I'm pretty confident that the system next year is secure and we will not have a repeat of the same problem we had this year."

Mr Tomlinson said the other key failure had been that the government had put in the scheme too quickly and had not piloted the new A2 exams - the second part of the A-level.

"That same set of problems cannot and will not occur next year or subsequently.

Minimising the risk

But he added: "It would a brave man who said however that nothing can go wrong.

"What we've got to do is ensure that we minimise the risk and manage the risk."

He said examining was not an exact science but "an art, in a number of ways", not least because human beings were involved, making judgments.

"But we've got to rely on those human beings as I do but to rely on them we've got to provide them with a framework that is clear and precise that they can work with and they can do their job properly.

"That is now happening, that's why I believe we can be secure about 2003.

"I may have, in 10 months' time, to say that something else happened which I could never have predicted - I have to be honest and say that's a possibility.

"I sincerely hope I don't have to do that."