He criticised police for move, saying he could have been killed by punch

Landlord was shocked to hear Mr Jackson had been let off with a caution

Mr Monks was rushed to hospital after attack, but had no serious injuries

Fight then ensued between the woman, another female and other drinkers

The single strike to the back of the head knocked Mr Monks unconscious

But as he stepped outside the premises, he was punched by Ian Jackson

Shocking CCTV footage has emerged capturing the moment a pub landlord was knocked unconscious with a single punch by a drinker who was later let off with just a caution.

In the surveillance video, Jason Monks, 46, is seen calmly escorting a woman from his pub - the Jolly Nailor in Atherton, near Wigan - following a disturbance shortly before midnight last month.

But as he steps outside the premises, the father-of-three is struck once in the back of the head by Ian Jackson, causing him to plummet headfirst onto the pavement, where he lies unconscious.

While the burly-looking Mr Jackson rushes away from the scene with the woman, another female inside the pub rushes to Mr Monks's aid, before calling for others to come out and tend to him.

Before the attack: In this newly-released CCTV footage, Jason Monks (far left, in a black top), 46, is seen calmly escorting a woman from his pub - the Jolly Nailor in Atherton, near Wigan - following a disturbance

Infuriated: The father-of-three is closely followed by Mr Jackson, who is clutching the woman's coat and bag

Shocking: As he steps through the pub's front door, Mr Jackson is filmed raising his fist and throwing a single punch (left), causing Mr Monks to plummet headfirst onto the pavement (right), where he lies unconscious

At this point, the woman who was escorted out returns to the scene and she and the other woman become embroiled in a violent brawl, just feet away from Mr Monks's unconscious body.

Seconds later, two men become involved in the fight, prompting others to try to tear them apart.

Mr Monks was taken to Royal Bolton Hospital following the horrific attack at around 11.40pm on November 20. However, he fortunately escaped from the incident without serious injury.

Today, the landlord lashed out at police for letting off Mr Jackson with only a caution, saying he could have been killed by the single punch - as has been seen in other pub and nightclub attacks.

Mr Monks, who has complained to GMP and Greater Manchester's Police and Crime Commissioner Tony Lloyd , said he told police in hospital after giving a statement that he wanted to press charges.

He said officers initially requested to see the sickening footage of the attack, but told him the next day that Mr Jackson had accepted an 'adult caution' after admitting his guilt and showing remorse.

They did not view the CCTV before letting him off with a caution, Mr Monks said.

He added that police said they had taken Mr Jackson's lack of previous convictions into account.

Late-night attack: Mr Jackson lowers his fist as he emerges from the premises shortly before midnight

Unconscious: Mr Monks (pictured unconscious outside the pub) was taken to Royal Bolton Hospital following the horrific attack at around 11.40pm on November 20. But he fortunately escaped without serious injury

Rushing to his aid: Today, the landlord (pictured being assisted by passerby) lashed out at police officers for letting off Mr Jackson with only a caution, saying he could have been killed by the drinker's single punch

In a statement about the 'strange' decision, GMP said all the circumstances were considered and a caution, as a criminal conviction, was deemed an 'appropriate course of action'.

Mr Jackson - who runs the Cadence Cafe community arts centre in Tyldesley - has yet to comment.

On the night of the attack, one surveillance camera captured Mr Monks - who has run the Jolly Nailor with wife Nicola, 47, since April - crashing head first onto the pavement outside the pub.

Another filmed the moment Mr Jackson, carrying his companion's bag and coat, threw the punch.

The attacker, who has now stepped down as chairman of community group the Tyldesley Town Partnership, was arrested at the scene. He was later cautioned after a period of questioning.

Mr Monks said: 'We were not even given a crime reference number and the police did not even view the CCTV. It was dealt with before we could give them the footage.

Another fight: In the footage, the woman who was escorted out (left) returns to the scene and she and another female (centre) become embroiled in a violent brawl, just feet away from Mr Monks's unconscious body

Furious: Seconds later, two men become involved in the fight, prompting others to try to tear them apart

Lashing out: Mr Jackson, who has now stepped down as chairman of community group the Tyldesley Town Partnership, was arrested at the scene. He was later cautioned by police after a period of questioning

'The police asked us if we wanted to press charges and we said yes.. We weren't even given the chance. It's shocking to release him with just a caution for something like that.'

Describing the moment he escorted the woman out of the Jolly Nailor following the initial indoor disturbance, Mr Monks said: 'We got to the door but before I could turn around that was it.

'I do not remember anything else. I only know what I can see on the CCTV. I woke up on the floor.

'I was told by the police that there was no need to see the CCTV because he had accepted a caution. They said he had admitted his guilt and shown remorse. I believe it was premeditated.

'He knew what he was going to do.'

Mrs Monks said she and her husband, as licensees, have supported 'one punch can kill' campaigns run by GMP. They are now taking legal advice.

Initial disturbance: Mr Monks decided to escort the woman out following a disturbance inside his pub (above)

Breaking it up: The landlord (pictured breaking up the disturbance) said: 'We got to the door but before I could turn around that was it. 'I do not remember anything else. I only know what I can see on the CCTV'

Scene: A police spokesman said an investigation was launched into the incident at the Jolly Nailor (above)

'I have worked behind bars for 30 years. I know what damage one punch can do and we've all read the horror stories. We are not at all happy with a caution,' said Mrs Monks.

'To receive a caution for that level of violence is just shocking. Jason was brutally punched to the back of the head and his head hits the floor with force. I thought he was dead.'

A police spokesman said of the incident: 'An investigation was launched and a man was arrested on suspicion of section 47 assault. The man was interviewed and all the circumstances of this specific case were considered. On this occasion a caution was issued.