A Labour councillor was badly injured after his bike was sabotaged and his brakes cut.
Police are investigating the crime which left the 22 year old with serious wounds when he hit a lamppost at the bottom of a hill near his home at 30mph.
Joe Day said that he was in "the worst pain he has ever experienced”, and endured surgery and a stay in hospital.
His finger was split to the bone in what police say was a ‘deliberate act’.
Joe, a former Manchester University physics student and TV quiz show University Challenge contestant, told the Telegraph: "The skin was hanging off it like a banana peel, looking at my finger made me queasy.
"It was split up and you could see the bone. I was distraught and shaken and losing a lot of blood from the finger wound.”
He added: "The people who did this might think it is a prank and will just cause a little bump or knock, but if you get up to speed you can seriously hurt yourself or other road users.
"There are other ways of having fun without putting people in serious danger."
Joe got on his bike at 1am on Wednesday August 19th when he finished his night shift at Asda, in Bideford, Devon.
He was perturbed to find a carrot wedged in his saddle but did not notice the damage to his brakes before he embarked on the 1.5 mile journey home.
Joe said that when he tried to brake: "I didn't know what to do, whether to bail out or try and ride the storm. This all happened in 30 seconds."
He broke his wrist, peeled the flesh back from his middle finger, chipped a bone in his finger and hit his head.
An expert who examined the bike following the crash, confirmed the brakes had been disconnected.
Despite being a local councillor, Joe said he did not think he had been deliberately targetted.
He said: "I am a Bideford town councillor - but I haven't done anything controversial yet. I think it was just random, untargeted.
"I want this to be a warning to other people, do check your brakes before you get on your bike, before you pick up speed, and wear helmets."
A spokesperson for Devon and Cornwall Police asked witnesses to call 101, quoting crime reference no. CR/057888/15.