A thug who launched a vicious and unprovoked attack on a fellow commuter in a row over pushing on a crowded train has been jailed for 10 years.
Joe Montgomery, 29, left his battered victim with a fractured skull and a bleed on the brain after unleashing repeated punches to the head and face.
Montgomery became involved in a verbal altercation with the 45-year-old victim over alleged pushing of bags after boarding a busy train.
Angry words were exchanged between the pair and, in a matter of seconds, Montgomery suddenly and without warning physically attacked the victim.
He repeatedly punched him seven times on the side of his face and head.
As a result of the attack, the victim sustained a depressed skull fracture and haemorrhage to the brain.
Police said he was knocked out from the force of the blows and was left with life-changing injuries.
In the footage, he is standing with his back to the camera and his hands raised in the air.
The victim is in a light-coloured jacket, bending down, barely visible behind his attacker.
Montgomery, of Croydon, pleaded not guilty, but was convicted of grievous bodily harm with intent and jailed for 10 years.
Sentencing Montgomery at Croydon Crown Court, the Judge described the attack as "savage and frightening" involving "uncontrolled violence" which has meant the victim "will never be the same again".
Detective Constable Rachel Smith, of British Transport Police CID, said: "This incident is a nightmare scenario for anyone who commutes on the trains regularly.
"We are all aware that sometimes on packed trains, there may be tension between passengers and occasionally verbal disputes, but Montgomery took this to the extreme by launching a sustained and horrific attack on a fellow commuter.
"The victim has been left with life-changing injuries as a result of this attack. He had no idea when he boarded the train to work that day that an exchange of words with a fellow commuter and a few seconds of violence would change his life so dramatically.
"I am glad that Montgomery has been found guilty of this offence and been given a suitable prison sentence."