Mr Fraser joined the SQA in 2001

David Fraser has resigned from the body responsible for Scotland's school exams "for personal reasons," said SQA chairman Sir John Ward.

The authority said Mr Fraser's decision came after the second successful delivery of national qualification exam results during his stewardship as chief executive.

The Scottish National Party claimed the resignation came amid rumours of funding disagreements between the authority and the Scottish Executive, a claim which the executive denied.

I am very pleased with the way the organisation has turned itself round and I am grateful for the contribution David Fraser made to that process Peter Peacock, Education Minister

"David Fraser has resigned for personal reasons and in his resignation letter wished to thank the SQA board and chairman for their support over the successful NQ diets of 2002 and 2003," said an SQA statement.

"The board and chairman wish David every success for the future."

Anton Colella, currently the SQA's director of qualifications, will act as chief executive until a successor is appointed.

Mr Fraser, 51, formerly a senior manager in the health service joined the exam body at the end of 2001.

He succeeded Bill Morton, the acting chief executive who took over after the departure of Ron Tuck in the wake of the exam fiasco in the summer of 2000 when thousands of youngsters received late or inaccurate results.

'Serious blow'

Education Minister Peter Peacock paid tribute to the departing exams boss, saying: "I am very pleased with the way the organisation has turned itself round and I am grateful for the contribution David Fraser made to that process."

But Nationalists said the resignation came amid "rumours of disagreements with ministers" over funding and described Mr Fraser's departure as "a serious blow" to Scotland's education system.

"We desperately needed a period of stability to build the confidence of pupils, parents and employers in the qualifications system," said SNP education spokeswoman Fiona Hyslop.

"This resignation gives the impression of an exam authority lurching from one crisis to another amidst rumours of a breakdown in relations with ministers."

But the executive denied the SNP claims.

"There are ongoing discussions with regard to the SQA's financial position, but we have certainly not fallen out," said a spokesman.