Piers Corbyn was a Labour Party councillor for a number of years. Previously he was a member of the Trotskyist International Marxist Group, who were influential in the late 1960’s/early 1970’s and later dissolved itself in Labour Party entryism. He was well known for his involvement in the campaigns around the Elgin Avenue squats.
From what I know he has always had something of a reputation, I remember people talking about him in the squatting movement of the late 80’s (the time he was a councillor), and not in a good way. Apparently he has always had a thing about weather forecasting but he was firmly entrenched in crankdom by the mid 90’s at the latest via dodgy long range weather forecasting and climate change denial. Interesting his Wikipedia entry notes notes that one Boris Johnson used his newspaper column to argue he was right on these issues.
