Blair Jenkins has been in the post for six years

Blair Jenkins, 49, announced what he described as a "very difficult decision" to staff on Wednesday.

He said: "It has been a fantastic privilege to lead the news and current affairs team at BBC Scotland."

Unions expressed surprise at what they described as "one of the most significant resignations at the BBC since the end of the Hutton affair".

Born in Elgin, Mr Jenkins first joined the BBC as a news trainee in 1980 after beginning his journalistic career with Aberdeen's Evening Express newspaper.

We owe him an enormous debt of gratitude Ken MacQuarrie Controller

He worked on the Nine O'Clock News and produced Reporting Scotland before joining Scottish Television in 1986, going on to become the station's director of broadcasting.

He was also chairman of Bafta Scotland for five years.

In his statement to staff, Mr Jenkins said: "It's been a pleasure and a source of no little pride to work with so many talented and committed people.

"There is so much journalism to be proud of - awards at a European and UK level for Frontline; Reporting Scotland and Newsnight Scotland; the fact that Good Morning Scotland is achieving its best audiences in 10 years; political coverage that is unrivalled for its range and depth; our Scottish news website which leads the BBC in much of its content and thinking."

He said he would be leaving the corporation at the end of August.

Digital future

There was a spontaneous round of applause from staff after Mr Jenkins made his brief statement in the Glasgow newsroom.

Controller Ken MacQuarrie said: "Blair has led news and current affairs confidently into the digital future.

"In an increasingly fragmented market, he has ensured that BBC Scotland continues to be the standard bearer and leader for news, political coverage and current affairs across Scotland on television, radio and new platforms.

"We owe him an enormous debt of gratitude."

It must be seen in the context of the growing anger among staff over the continuing job cuts, threats of compulsory redundancies and the BBC's attack on the staff pension scheme Peter Murray National Union of Journalists

National Union of Journalists representative Peter Murray expressed "genuine surprise" at the decision.

"He had presided over a period of intense change in the department, most recently forced upon us by Director General Mark Thompson's attack on jobs and programme budgets across the BBC," he said.

"Blair Jenkins' departure is therefore one of the most significant resignations at the BBC since the end of the Hutton affair.

"It must be seen in the context of the growing anger among staff over the continuing job cuts, threats of compulsory redundancies and the BBC's attack on the staff pension scheme."

Staff, who staged a 24-hour strike last year over the cuts, are set to be balloted on further industrial action over pay and pensions.

"Whoever is chosen to replace Blair Jenkins, journalists at BBC Scotland will not accept a management bean-counter who seeks to impose further job cuts and swingeing savings on the premier news and current affairs department in Scotland," added Mr Murray.