Police are appealing for help to trace a witness to an incident that has left a man in a serious condition in hospital.
Officers were contacted by staff at a central London hospital at around 08:44hrs on Friday, 7 December after a 33-year-old male was transported there by London Ambulance Service paramedics and rapidly lost consciousness upon arrival.
He had been discovered in High Holborn, near the junction with Grape Street.
Doctors carried out tests and the victim was discovered to have had a bleed on the brain.
It was suspected that he may have been assaulted and so medical staff informed police.
Officers carried out CCTV enquiries and established that the victim had been assaulted outside Flight Club, Bucknall Street junction with Dyott Street.
The man pictured intervened to stop the attack and helped the victim.
At this time there have been no arrests.
Enquiries are ongoing to trace those involved.
T/DC Chris Shepherd, of the Central North Command Unit, is leading the investigation. He said: "I reiterate that this man is sought solely as a witness. We need to speak to him as he may hold vital information that could assist us.
"The victim remains in a serious condition in hospital, with his next of kin at his bedside. I would ask anyone who knows the male to contact us as quickly as possible."
Anyone who recognises the witness is asked to call 101 quoting CAD 2996/7 Dec.
Alternatively tweet @MetCC.