Robin Harper, the veteran leader of the Green cause in Scotland, is standing down from the party leadership with a reform plea to his party.

The Lothian MSP, 68, became the first Green parliamentarian in Britain when he won a seat at the first Scottish Parliament elections in 1999.

He gives up his leadership role in November, when a replacement will be elected, and he is to stand down from parliament at the 2011 election.

He said it was time to give way to a younger leader "with bags of energy". His sole Green MSP colleague, Patrick Harvie, who represents Glasgow, is in pole position to replace him.

In his resignation statement, he said he is not retiring.

"I expect to see few changes in my lifestyle," he said. "I made up my mind that I didn't wish to stand for a fourth term in the Scottish Parliament, so the earlier the party re-organises under a new co-convener, the better."