Police are looking for a man seen strolling through the barriers of a Tube station minutes before a stranger was stabbed in a vicious knife attack.
Fresh video footage has been released showing a man at Snaresbrook Underground station shortly before he stabbed the victim aboard a Central Line train.
Police said the victim had a “lucky escape” as the knife narrowly missed a vital artery.
The victim, a 50-year-old man, was on the train at around 1.20am when he became involved in an argument with a group of passengers on the train between Snaresbrook and Leytonstone.
Police said the group grew “antagonistic” and one of the men ran at the victim, pulling out a knife and stabbing him in the leg.
The victim was left with a serious knife injury and was rushed to hospital.
DC Jon Howlett, who is investigating with British Transport Police, said: “This was a lucky escape for the victim as the knife narrowly missed a vital artery in his leg.
“Whilst the victim’s physical injuries continue to heal, he will always live with the terrifying ordeal he suffered that night.
“Thankfully, violent assaults such as this are very rare on the railway. However, when they do occur we will do everything in our power to trace those offenders and bring them before the courts.”
Police are releasing new images of the man they want to speak to in connection with the stabbing, which took place on October 22 last year.
The video shows him strolling through the ticket barriers as another man, who police say is a member of the public, dives underneath.
Police added they would also be interested in speaking with the man who dives under the barriers in case he has any information which could help.
Anyone who has information is asked to text 61016 or call 0800 40 50 40 quoting reference 178 of 30/03/2017. Alternatively, contact Crimestoppers anonymously on 0800 555 111.