One told Cambridge News: "I heard gasps and I turned around - it was a horrible sight.
"It's fair to say he was overexcited and got aroused.
Police had a stern word with the bike enthusiast, who was said to have looked 'sheepish' as he was giving a telling off.
Apparently his reaction to the view of countless naked cyclists was expected by event organisers, who previously told those taking part: "The police have confirmed they WILL act on ANY inappropriate behaviour and we, the organisers will support that.
