Mill Hill shop worker fighting for life after attack
A shop worker is on life support after being "violently attacked" after refusing to serve three teenagers.
Police say two shop employees were assaulted after they "rightly refused to sell items to youths they believed to be under age".
One of the men, 49, is on life support in hospital, while his colleague suffered minor injuries.
The attack happened on The Broadway, Mill Hill, at 23:45 GMT on Saturday.
Police are appealing for help to trace the suspects, described as three black males, all believed to be youths.
They ran away from the scene shortly after the attack, police said.
DI Ian Lott from the Metropolitan Police's homicide and major crime command said: "We understand that a number of people came to [the 49-year-old's] aid and helped to put him in the recovery position.
"Were you there? Did you see the suspects running away? Some witnesses may have video footage during or after the attack and we would urge them to get in touch with investigators."
A police spokeswoman said the nature of the items the teenagers were attempting to buy could not be revealed at this stage.