Detectives investigating the murder of a new father have made an arrest.
Reece Newcombe, 31, was fatally stabbed with a piece of glass in a fight on Richmond Bridge in south-west London in the early hours of Saturday.
A 32-year-old man went to a police station in west London on Monday afternoon and was arrested on suspicion of murder.
Tributes have been paid to Mr Newcombe, who worked as a boxing trainer with celebrities including former footballer Ian Wright.
His family said in a post on Facebook that they are "truly heartbroken".
Former boxer Barry Jones said on Twitter that Mr Newcombe was "such a lovely, charismatic and caring person and a talented boxer".
An online appeal for funds for his baby daughter has already raised more than £50,000.
Detectives investigating his murder believe a number of people watched the fight and several filmed what happened on their mobile phones.
Metropolitan Police Detective Chief Inspector Katherine Goodwin said: "Anyone who has yet to speak with police is urged to come forward immediately.
"We believe a number of people watched the incident unfold and some onlookers may have recorded footage on their mobile phones.
"I need to hear from all of these people."
Anyone with information can call police on 101 or tweet @MetCC quoting the reference CAD 1099/26NOV, or to remain anonymous contact Crimestoppers on 0800 555111 or online.