Shocking footage has emerged which appears to show a uniformed policeman attacking a car in north London after the driver does not get out.
The video, shared on Twitter on Saturday and viewed by thousands of people, shows a uniformed police officer repeatedly telling him to "get out of the car", saying the driver is "not allowed to drive it".
The officer then hits the driver's side window with what appears to be a baton.
The driver, who filmed the footage on his phone, can be heard saying "I've got a licence. I've got insurance. You're smashing this for no reason."
The policeman can be seen hitting the windscreen, shattering the glass over the dashboard.
And then he retrieves what looks like a pen knife and starts slicing around the damaged area.
A man who wanted to be referred to by his first name, Leon, told the Press Association he was the driver in the video.
He said it was a "case of mistaken identity" and a "completely unlawful act".
The incident took place at around 5pm on Friday evening in Camden.
Leon said he spent the night in hospital as he had glass in his eyes and said he was "still in shock" over the incident.
"Every time he smashed the glass, fragments of glass were just ricocheting in my face," he said.
Metropolitan Police said they are aware of the footage and immediately contacted the Directorate of Professional Standards (DPS) to launch an investigation into the incident.
It is not clear what action the DPS may take, and neither of the officers seen in the footage have been suspended or placed on restricted duties.
Police say no one was arrested at the scene.
As to the car's damage, according to a parliamentary research briefing, police forces "do sometimes make ex gratia payments or pay compensation following such damage, for example where the raid was at the wrong premises."
But a Met Police spokesman told ITV London he could not comment further.