This shocking footage captures the moment a motorbike rider straddled a police officer and swung blows at him before being dragged off by passers-by.

Dashcam film, caught by a passing driver, shows the man appearing to launch a flurry of blows at the officer during a struggle in the road.

The incident ends as members of the public rush to support the officer, who did not suffer serious injuries.

Trouble flared when an officer from Merseyside Police’s Roads Policing Unit pulled over a motorbike rider in Litherland on Wednesday morning.

The officer stopped the man on Gorsey Lane at around 11am over suspicions he may have been riding without a valid MOT or Road Tax.

A spokeswoman for the force said the biker then assaulted the officer.

The film shows the officer lying on the floor and attempting to defend himself as a man sits on top of him, launching blows in his direction.

Passers-by then rush in to help the officer and pull back the man on top of him.

The force today confirmed a 39-year-old man from Maghull had been arrested in connection with the incident.

The spokeswoman explained: “At around 11am an officer from the roads policing unit stopped a motorcyclist on Gorsey Lane, as the officer suspected the motorbike was being used without a valid MOT or road tax.

“The motorcyclist then assaulted the officer, before PCSOs and members of the public stepped in.

“The man was arrested on suspicion of assaulting a police officer and other motoring offences. He was taken to a police station and has been released pending further enquiries.

“The officer suffered cuts and bruises and remained on duty.”

The incident is the latest over recent weeks in which officers have been targeted.

Seven voluntary officers were assaulted last week while on duty, with some special constables allegedly attacked as they took part in a disruption operation in Litherland.

And in Fazakerley, officers from the Roads Policing Unit had their tyres let down at the scene of a fatal scrambler bike crash.

Yobs were also said to have spat on the door handles of police cars at the scene.

Following the incident yesterday, Acting Chief Inspector Keith Kellett, from the Roads Policing Unit, said: “Thankfully the officer was able to remain on duty and suffered only minor injuries, and we’d like to thank the members of the public and other officers who came to his assistance.

“This officer was simply trying to do his job and I’m sure the public would agree that officers who are keeping our roads safe, should not be subject to behaviour like this.”