Results will be posted to pupils on 14 August

Last year the SQA was at the centre of a crisis as thousands of pupils received results which were either late or inaccurate.

It held a briefing on Friday to reassure the public that its computer systems and marking arrangements had worked properly this year.

"There are a very small number of candidates who, for a variety of reasons, we just wanted to do a final check," said Mr Morton.

"In many instances this is the fourth check, given that the schools and colleges themselves have checked the information on at least three occasions.

"We believe that these checks are necessary to be absolutely sure that when the candidate receives the certificate they can know that it is complete and accurate.

All the checks we have in place allow us to know that the intention to certificate accurately and on time on 14 August is something that we firmly believe will happen

Bill Morton

"I want to stress that this isn't about problems - I don't want candidates being concerned about this.

"Most of these checks will confirm that information we hold on the candidate's behalf is entirely accurate, so no change will be required."

There are a number of reasons for results being checked, including cases where candidates appear to have passed the final exam without taking part in some or all of the internal assessments.

Mr Morton said that everything that could be done by the SQA to ensure the accuracy of this year's results had been done.

And he pointed out that this had been a record year, with staff having to deal with the largest ever examinations diet and 4.25m exam papers.

He paid tribute to the efforts of the SQA staff, whom he said had faced a real challenge.

Mike Russell: "Stark truth"

And he added: "We have been extremely diligent that all the checks we have in place allow us to know that the intention to certificate accurately and on time on 14 August is something that we firmly believe will happen - and with good reason."

SQA chairman John Ward also offered a public "thank you" to the SQA staff on behalf of its board.

However, he also said he was still working to a three-year recovery plan and added there was "a lot still to do".

Scottish National Party education spokesman Michael Russell welcomed the progress which had been made.

But he added: "Thousands of young people in Scotland will remain worried as long as there is the possibility of a single doubtful result.

Process information

"The SQA and the Scottish government should bear that stark truth in mind over the next 10 days as work goes on to finish the results process."

And the chief executive of the organisation which handles university and college admissions, Ucas, said he still had concerns about the SQA's ability to process information for all candidates on time.

Tony Higgins said: "We are concerned, and Bill Morton knows this, that the SQA have interpreted the Data Protection Act rather differently from the other examining boards.

"We are worried that we won't get all the results for all the candidates on time for us to be able to convey them to the universities."

Mr Morton said he understood Mr Higgins' "scepticism", but said the Ucas chief executive did not have the understanding of the new systems being employed by the SQA this year.