Police officer under investigation after video emerges showing a violent attack on male who had been detained

Police probe launched following footage of a man punched and kneed in head by a police officer while being pinned down

The male officer was filmed bending down next to the detained man and is seen to thump him hard in the face during the incident in Portsmouth, Hampshire and Isle of Wight Constabulary have since launched an internal investigation.

The shocking video shows police repeatedly striking a man who was pinned to the floor, Pinned down in the road by three officers, a shirtless man is brutally attacked as he is seen to be kneed and punched in the head by the policeman.

A passerby filmed the scene and police last night confirmed they are investigating the actions of the officers involved.The footage was recorded on a phone camera after a man was detained in Portsmouth.

As large numbers of public went about their business, at least three officers were filmed pinning the suspect to the road. The male officer was then filmed bending down next to the detained man and thumping him hard in the face. Footage also appeared to show the officer delivering several blows with his knee and an arm being placed over the suspect’s neck.

Official guidelines state police can legally use “reasonable” force when making an arrest – but only when it is deemed “necessary”.

Former Scotland Yard detective Peter Bleksley said: “Neck restraint is dangerous and can cause asphyxiation – it should be avoided.

“If a suspect is not attempting to bite or spit, punching and blows to the head would not normally be considered proportionate or reasonable.”

Hampshire Constabulary said the video was taken during an arrest made at 5pm on February 1.

A 39-year-old was detained on suspicion of assault – including of a police officer – and possessing an offensive weapon in public and bailed.

No one was seriously injured in the altercation, police said, and the force is appealing for witnesses.

A source said the detained man complained the incident left him traumatised and in severe pain.