A police sergeant found guilty of head-butting a woman in a "road-rage" attack while wearing a motorcycle helmet has been fined £828.
David Sanderson was off-duty when he approached two women in their Ford Fiesta, believing they had been using a mobile phone while driving on 6 June last year.
Gaynor Byng, prosecuting, told the court the phone was being used hands-free, and described Sanderson, 45, revving his motorcycle engine behind, them at the Asda petrol station in Chandler's Ford, Hampshire.
She told Worthing Magistrates' Court that Sanderson, of Portsmouth, had then attempted to undertake the car before it stopped, at which point passenger Donya Bryant got out and confronted him.
Ms Byng said: "He began shouting at them, telling them they shouldn't have been on the phone."
As the situation escalated Miss Bryant, who was upset at the recent bereavement of a friend, swore at Mr Sanderson and threatened to kill him, the court heard.
It was at this point that Mr Sanderson head-butted Miss Bryant while still wearing his crash helmet, Ms Byng said.
She described the attack as leaving "a red mark the size of a 50p piece and a swollen lump" on Miss Bryant's forehead.
Ms Byng said Sanderson told another off-duty police officer who had witnessed the incident: "You do not know what you saw, young man. I am police too."
Sanderson had denied assault by beating and was found guilty following a trial last month.
At Monday's hearing he was fined £828 and ordered to pay court costs and £100 compensation to the victim.
Chairwoman of the bench Marley Isaac told Sanderson while they were "mindful" of his "position in the force", "previous good character and 23-year exemplary service", she also considered it to be a "road rage incident".
Commenting on the intimidation the victim would have felt as Sanderson revved his engine, she also told him he should have identified himself at the moment the situation escalated.
Paul Fairley, defending, said Sanderson continued to deny that he deliberately assaulted Miss Bryant and the case was set to go to the crown court for appeal.
He said the officer was fulfilling his duty of preventing the use of mobile phones at the wheel.
Mr Fairley said: "He is the sort of officer who would always seek to educate those who seek to drive dangerously or put themselves and others at risk."
He said Sanderson was still working full-time for Hampshire Police, but faces dismissal from the force and has been taken off front-line duties pending the conclusion of the appeal.