Detectives are appealing for assistance in tracing a witness who intervened during an incident.
At around 02:30am on 12 October, the 35-year-old victim had an altercation with two other males in Paul Street, Shoreditch, where the victim ended on the floor with a deep laceration to his jaw.
A passing cyclist intervened, causing the two males to make off on foot. He then helped the victim get into a black cab.
Detectives from Hackney CID are keen to trace this cyclist, who is likely to be a crucial witness.
He is in no way considered a suspect; police need to speak to him to further clarify what happened.
Two males, both aged in their early 20s, were arrested on 18 November on suspicion of GBH. They have been released under investigation. Nobody has been charged at this stage.
Any witnesses or anyone with any information is asked to call Hackney CID on 07825 793 215 or 101, or contact via Twitter @MetCC.
To give information anonymously contact Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.