Police have released sickening CCTV images of a robbery victim being knocked unconscious by a single punch as he walked home from a party.
Footage of the attack in Birmingham, lasting almost two minutes, shows a plate being thrown at the victim to distract his attention moments before he is knocked to the ground.
The victim, aged 51, is seen lying motionless as one mugger searches his pockets while another offender repeatedly kicks him to the head.
More than a dozen vehicles can be seen driving past the scene of the attack before a concerned passer-by alerts the emergency services.
The victim, who has asked to remain anonymous, was attacked in the early hours of December 15.
In a statement issued by West Midlands Police, the man urged members of the local community to provide police with information to catch the "cowards" responsible for his injuries.
"This community will not tolerate or accept crimes such as the one inflicted on myself, and people should be safeguarded from these thugs," the victim said.
"On the advice of others, I have chosen not to view the CCTV, but I want such cowardly perpetrators to know the psychological damage you inflict on innocent people can be irreparable."
Chief Inspector Dawn Miskella, from Birmingham CID, said: "The footage speaks for itself - it was an absolutely horrendous, unprovoked attack on an innocent man who was making his way home from a night out, leaving him with long-lasting injuries.
"He suffered extensive cuts to his face and head which required stitches and will leave permanent scarring, along with other cuts and bruises to his body.
"There's also the psychological impact of the assault and, of course, the loss of his watch and phone.
"I would appeal directly to those people who drove past the scene as the robbery was taking place to please come forward and speak to us.
"You may not have realised what was going on at the time, but your information could be vital in helping us find the people responsible."
The attack happened near a doctors' surgery on Bordesley Green, at its junction with Pikewater Road, at around 1.10am.
Anyone who can assist the investigation is asked to contact Birmingham Police CID on 101 or the independent charity Crimestoppers anonymously on 0800 555 111.