A Victorian policeman retained his job and rank despite being caught on CCTV assaulting a drunk disability pensioner at Geelong Police Station.

Key points: Phil Dickson was assaulted by police officer Michael Cooke in 2013

Phil Dickson was assaulted by police officer Michael Cooke in 2013 Mr Cooke pleaded guilty to common law assault and no conviction was recorded

Mr Cooke pleaded guilty to common law assault and no conviction was recorded Mr Cooke was suspended with pay for approximately 12 months

Revelations about the handling of the case by Victoria Police come amid growing pressure on the State Government to back reforms of the state's police complaints system.

And today The Age reported the case of an Aboriginal teen wrongly arrested and allegedly subjected to police brutality.

Reform of the complaints system is supported by a joint parliamentary committee.

The victim of the Geelong Police Station attack, Phil Dickson, joined the calls for reform after learning the policeman who assaulted him avoided being sacked.

Mr Dickson said in his case, the system appeared designed to "protect the police officer".

Slapped, thrown to the ground in police station

Phil Dickson was assaulted by a police officer at Geelong Police Station. ( ABC News: Chris Gillett )

On January 11, 2013, Mr Dickson was found by police sitting in his parked car outside a supermarket in regional Victoria with a blood alcohol reading of 0.27.

It was after he had recently separated from his wife.

Mr Dickson, then 62, was arrested for drink-driving offences and assaulting an officer and pleaded guilty to those charges.

Once inside Geelong Police Station, CCTV footage that has never been made public before appears to show Mr Dickson being told to take off his belt, which causes his pants to fall down.

Mr Dickson throws his belt on the ground, then senior constable Michael Cooke hits him on the head and throws him forcefully on the ground.

Mr Dickson suffered a serious head injury and required immediate hospitalisation.

"I thought I must have tripped," Mr Dickson told 7.30.

"I had a break in that knuckle. I had a torn ligament in my shoulder."

Medical records said Mr Dickson was intoxicated in his cell and was rowdy so had to be physically restrained, and hit his head.

But the CCTV seems to tell a different story, with the assault taking place at the front of the police station.

Legal Aid asked for access to the CCTV vision due to the extent of Mr Dickson's injuries.

After he saw the vision, Mr Dickson made a complaint to Police Professional Standards, and more recently to IBAC, the anti-corruption commission.

Officer pleads guilty to common law assault

An image from the CCTV footage shows police officer Michael Cooke assaulting Phil Dickson. ( Supplied )

Mr Cooke pleaded guilty in the Geelong Magistrates' Court to assaulting Mr Dickson.

Mr Cooke was initially facing a more serious charge of recklessly causing injury, but struck a plea deal with prosecutors to have the charge reduced in return for a guilty plea but no conviction.

He was suspended with pay for approximately 12 months.

Mr Cooke returned from his paid suspension to face an internal police disciplinary hearing in 2015.

The hearing panel reviewed the CCTV of his assault on Mr Dickson and placed Mr Cooke on a good behaviour order.

He remained a police officer until 2018, when he resigned.

In a statement, a Victoria Police spokesperson said: "Make no mistake, this is not the manner in which we expect our officers to behave. We do not condone violence.

"That is why the incident was thoroughly investigated by Professional Standards Command and the officer was charged with the criminal offence of recklessly cause injury. All available information and evidence was heard in an open court.

"There is no doubt the CCTV footage was confronting and was considered by the hearing officer, however Victoria Police must take into account a range of factors such as the court verdict, character references and relevant employment law when making a decision about an officer's ongoing employment.

"The community should be assured that Victoria Police is committed to continually improving our internal processes for investigating complaints against its officers."

Since the incident, Mr Dickson has been through drug and alcohol rehabilitation and now volunteers at a local charity shop.

"I could have been dead and I'm sure nobody would have asked, 'Is there any CCTV footage about that?'" he said.

Teenager wrongly arrested

Tommy Lovett's injuries. ( Supplied )

Mr Dickson's case was one of a number uncovered by The Age and 7.30 over the past 12 months.

Today The Age revealed the case of an Aboriginal teen wrongly arrested by police and allegedly assaulted in April 2016.

The Age and 7.30 uncovered police statements and diary notes that support Tommy Lovett's claim that he was thrown into a fence and assaulted while handcuffed.

A uniformed policeman described Mr Lovett's arrest in his diary.

"When some of the information about how the incident was handled sank in … it was disappointing and disturbing to say the least," the diary note read.

Mr Lovett was a skinny, baby-faced 18-year-old riding a scooter to his grandmother's home when he was arrested.

Injuries to Tommy Lovett's face. ( Supplied )

Police had earlier issued a description of a 40-year-old Aboriginal man with a goatee suspected of stealing a car and ramming a police vehicle.

Mr Lovett's mother, Doreen Lovett, alleged her son's arrest was the result of racism and that he had been treated brutally.

An internal police investigation found nothing wrong with Mr Lovett's arrest.

A police spokesperson said a complaint was made alleging excessive force, which was later withdrawn.

"Situations like this are extremely dynamic and police are acting on real-time information," the spokesperson said.

"From time to time police make mistakes, which is what occurred when the 18-year-old was incorrectly arrested."

Watch this story tonight on 7.30.