A man has been jailed for killing a grandfather after the attack was filmed by a bystander wearing “spy cam glasses” in what is thought to be a legal first.
The second blow knocked Mr Glenn unconscious and he died in hospital almost a month later, having never regained consciousness.
Footage from a pair of glasses, which were bought for £7 on eBay and featured an integrated camera and microphone, was shown in court after the witness wearing them spoke to police.
It is believed to be first time such a device such has helped lead to a successful prosecution.
The court heard Mr Glenn was walking past the Golden Last pub on 1 September last year when some friends beckoned him inside.
The grandfather was involved in a fight inside the pub, during which he brandished a glass at another man, the Scarborough News reported.
An acquaintance of Collinson, who was outside the pub, reportedly suffered a cut on his cheek during the altercation.
On hearing about what had happened, Collinson went back inside the pub and punched Mr Glenn in the face.
The self-employed skipper, who has a history of violence, then punched Mr Glenn a second time as he was attempted to leave.
Ambulance crews attempted to resuscitate Mr Glenn before he was taken to Scarborough District Hospital and placed into a medically induced coma.
He did not respond to treatment and died on 27 September.
Detective Inspector Jonathan Sygrove, from North Yorkshire Police, said: “Collinson has a long history of violence and assault and his sentence clearly reflects the seriousness of his most recent offence which resulted in the tragic loss of a man’s life.
“His actions have caused a huge amount of pain for John Glenn’s family and this is something they will have to deal with for the rest of their lives.”