Officers are releasing images of two men they would like to speak to in connection with assaults outside a casino in Edgware.
The incident happened on Tuesday, 5 July, at around 00: 30hrs, after the suspect, had been asked to leave the Silvertime Casino in Burnt Oak Broadway.
He left, but returned a short while later with a second man. He then approached a member of the public, a man aged in his late 40s, and punched him.
The victim suffered serious head injuries and was taken to hospital where he was found to have two separate bleeds on the brain.
His condition was critical and he required months of treatment, he has now been discharged from hospital but is still recovering.
This assault is being investigated as grievous bodily harm.
Meanwhile, the second man who had returned to the scene with the suspect above, threw a can of drink and then assaulted a man, aged in his early 40s.
This assault was a slap and no serious injury was caused. This is being investigated as a common assault.
Both suspects made off from the scene and both are believed to have had east European accents.
Detectives from the local policing team in Barnet have carried a number of enquiries and are now in a position to release CCTV of the pair.
Detective Constable Dipesh Raithatha, said: “A member of the public who was enjoying a night out has been assaulted and was left in a critical condition. He spent months in hospital and now faces months of further treatment.
“We are asking for the public’s help and we are asking anyone with information to call police; you can also contact Crimestoppers if you do not wish to give your name. However you wish to contact us please tell us what you know, it could be the vital bit of information that helps us find those who were involved.”
Any witnesses or anyone with any information is asked to call police on 101 or contact via Twitter @MetCC. Please quote CAD 1522/21SEP
To give information anonymously contact Crimestoppers on 0800 555 111.