A former Devon charity boss who threatened a security clamper has been found guilty of assault and criminal damage.
Kevin Wright, 46, of Kenn, near Exeter, cut through the clamp chain and used it to threaten John Young.
Plymouth Magistrates' Court heard Wright was furious when his car was clamped outside Exeter's Central Station last May.
Wright, who denied the charges, was given a 12-month supervision order.
He was ordered to do 80 hours of unpaid community work and pay £799.85 in compensation and £400 costs.
The court was told Mr Young from Sapphire Security put a wheel clamp on Wright's Peugeot which was parked outside the station late at night with no ticket displayed.
"A short time afterwards I could hear the grinding sound of metal being cut and I saw somebody cutting the clamp off," Mr Young told the court.
He called for police help after being threatened with "brain damage" as he attempted to take photographic evidence."
A short time later Mr Young said a "ranting" Wright began to approach him swinging the 2ft (60cm) clamp chain and threatening to kill him.
"I could not believe what I was seeing," Mr Young said.
"He came round the van and smashed the chain down either side. He was controlled, cold and calculating."
Mr Young used a karate kick to defend himself, knocking Wright to the ground.
Wright, who set up a children's cancer charity after his son was diagnosed with leukaemia, claimed the signs at the station were designed to deceive drivers so clampers could "lie in wait" for drivers and claim the £100 release fee.
During a police interview, Wright admitted striking the clamper's vehicle, which he said was not marked.
"It was not about the £100 - it was about being extorted in the middle of the night," he said.
Mr Eoin MacCarthy, prosecuting, said the charge of common assault did not relate to any physical contact but to the threat made to Mr Young.