Graeme Pearson was appointed to the post in 2004

Graeme Pearson, director general of the Scottish Crime and Drugs Enforcement Agency (SCDEA), is expected to step down in November.

Mr Pearson was appointed to the position in 2004.

The Paisley-based SCDEA investigates serious and organised crime, including drug trafficking, money laundering and kidnap.

Awarded medal

Mr Pearson told the Herald newspaper: "The time is right after nearly four decades to step down.

"I would have to leave in just over two years anyway, and that means I don't have enough time left to deliver on some of the changes needed for the agency to be best-placed for the next five to 10 years.

"This has been a difficult decision which I have thought about for a long time this summer."

Mr Pearson has almost four decades of police service.

He joined what was then the City of Glasgow Police, now Strathclyde Police, in 1970.

The Glasgow University graduate rose up the ranks to Deputy Chief Constable and was awarded the Queens Police Medal in 2002.