A criminal fled a crime scene on his bike - only to collide with a BMW a short time later.
James John Beeston , 28, of Mount Road, Fleetwood, had approached mechanic Andrew Sumner, 56, as he walked back to his car after having his lunch and pulled a bladeless knife handle on him.
Beeston - who turned out to be the great nephew of the victim's employers - approached him as he tried to get into his Mini Clubman which was parked on Abbot's Road, Fleetwood, at about 12.40pm on September 6 last year.
He started to talk about where he worked - but he then demanded the motorist's car keys.
Beeston has been caged for 10 months after admitting affray.
Jane Dagnall, prosecuting at Preston Crown Court, said: " Previous to this, builders in the area have seen him arrive on his bike
"Mr Sumner gets out, forces the door against the defendant, and walks off.
"The defendant gets in the car but to no avail because there's no keys."
Half an hour later Beeston rode across a roads junction in Fleetwood town centre and collided with a red BMW, suffering injuries.
In his statement, the victim said he was "left fearful" adding: "I really thought he was going to harm me."
Sharon Watson, defending, said Beeston sent a five page letter to court saying: " I'm so, so embarrassed about all of this and I feel deeply sorry to Mr Sumner to feel the way he did."
She added: " He recognised even at an early stage his conduct was criminal and caused understandably distress on the part of Mr Sumner."
The Honorary Recorder of Preston, Judge Mark Brown, said: "Very quickly you demanded the car keys and produced what Mr Sumner thought was a knife, but in fact turned out to be the handle of a knife.
"He was threatened but instead of handing over the car keys he got out of the vehicle, kept the keys with him, shut the door and walked away.
"You then got into the car and you remained in the car for a couple of minutes before you got out, went back to your bike and drove off.
This was a relatively short incident. No actual force was used, and Mr Sumner acted in a very public spirited and sensible way when he simply got out of the car and returned home.
"You rode off, your description was circulated by police and about half an hour later you were seen riding your bike. You crossed a junction and in doing so collided with a vehicle.
"Police officers involved in your arrest described your behaviour as erratic, unusual and somewhat aggressive."