An off-duty police officer shunted into another driver’s Mercedes in a road rage row at a motorway toll booth, a misconduct hearing has been told.

Blackwood-based PC Dean Harris, 47, is accused of grabbing the Mercedes’ wing mirror while hanging out of his car window on a busy motorway.

The hearing was told PC Harris accused the other driver of hitting his wing mirror as he drove through tolls, which were then in place, on the Severn Bridge from England into Wales.

The Mercedes driver – named only as Mr W – heard a “bang” before he saw PC Harris pull alongside him saying: “You smashed my f***ing mirror.”

Jonathan Waters, representing the force, said PC Harris was “incensed” by the alleged collision and leaned out of his window to grab the driver’s mirror.

Mr Waters said: “PC Harris attempted to damage the mirror by hitting it with his open hand and pushing it as far as it could go.”

He said the officer then started to flash his lights and swerve from right to left.

The Merecedes driver then felt PC Harris “shunting” the back of his vehicle – but could not escape across over the lanes of traffic to reach the hard shoulder.

The driver then called police on his way home to report the incident – not realising PC Harris was an off-duty officer.

Giving evidence, the driver said there were “three or four distinct lanes” of traffic as he drove through the tolls into Wales on the M4.

He had let one driver into his lane but saw a red Vauxhall, driven by PC Harris, on his passenger side.

He said: “He kept shouting “You smashed my f***ing mirror.

“He was grabbing my mirror and he was rocking it back and fore and he was swearing.

“He was hitting it with the butt of his hand and then it turned the wrong way.

“The man was so angry he was trying to damage my car and I moved forward so he couldn’t do any more damage.”

The driver then said he felt an impact as PC Harris was behind him and heard a “slight thud.”

He added: “I just decided something needs to cool down. It was getting silly.

“It was going through my mind that he was doing his best to inflict damage to my car.

“When somebody cuts into a lane of traffic you are in, I don’t think you are at fault.”

The hearing was told PC Harris – who was driving his parents home from holiday – then got out of his car to confront the driver on November 9, 2018.

The driver added that he drove away as he was “quite fearful.”

PC Harris faces allegations of gross misconduct at the hearing in Cwmbran.

He denies five allegations of breaching Standards of Professional Behaviour.

The hearing that he “shouted aggressively and repeatedly at Mr W using offensive words.”

The charge also states: “You repeatedly sounded your car horn in order to intimidate Mr W.

“You caused your vehicle to collide with the rear of Mr.W’s vehicle in anger and as a means of intimidating him on one or more occasions thereby causing damage.

“You got out of your vehicle in order to confront Mr. W and shouted at him continuously and aggressively using offensive words.”

The hearing, due to last four days, continues at Gwent Police HQ.