The brutal moment a man has his head slammed into the counter at a police station - as he expresses shock none of the cops involved will be punished and chases compensation for a brain injury

A father-of-four has expressed his anger after four police officers were cleared of any wrongdoing during his violent arrest.

Nathan Cross claims he was knocked unconscious and suffered permanent brain damage when officers slammed his head into the front counter of Victor Harbour Police Station in 2017.

The confronting altercation was captured on CCTV, showing the moment the 43-year-old knocked unconscious by.

Nathan Cross  claims he was knocked unconscious and suffered permanent brain damage when officers slammed his head into the front counter of Victor Harbour Police Station in 2017

A father-of-four has expressed his anger after four police officers were cleared of any wrongdoing during his violent arrest

He was then led into the station following his arrest, barefoot and handcuffed, 7 News reported.

Earlier this year Mr Cross was found not guilty over assault charges and has since launched civil action against SA Police over the officers' conduct.

But on Wednesday SA Police announced no criminal charges would be laid against the officers involved.

Mr Cross was shocked by the result and is now filing for compensation after claiming his life was changed on the day of the incident.

'His memory's been affected, his personality's been affected ... everything about his life has been affected,' his lawyer Andrew Carpenter said.

Mr Cross said he did not understand why the officers weren't being charged after inflicting lifelong injuries.

'There should be a detailed inquiry from ICAC and SA Police,' he said.

The confronting altercation was captured on CCTV, showing the moment the 43-year-old knocked unconscious by

He was then led into the station following his arrest, barefoot and handcuffed

In documents filed by the 43-year-old's legal team, lawyers allege the officers breached their duty of care.

'They attempted to cover up the assault by providing a series of false and misleading statements,' the documents read.

Lawyers acting for police are urging for the injury claim to be postponed after an internal investigation is completed.