Five gang members who were "caught red-handed" with machetes and baseball bats after making drill rap videos glorifying violence are facing jail.
Micah Bedeau, 19, Yonas Girma, 21, Isaac Marshall, 18, and two 17-year-olds, who cannot be identified, had an array of weapons when they were arrested in Notting Hill, west London.
They are due to be sentenced at Kingston Crown Court on Thursday for conspiracy to commit violent disorder, according to the Metropolitan Police.
Officers swooped on the gang after they featured in seven videos on YouTube wearing balaclavas and full face masks.
The footage, which has since been removed, featured sounds of gunshots and lyrics glamourising violent crime, police said.
They were stopped in Colville Square on November 9 last year after a two-year investigation.
The men were armed with four large machetes and baseball bats, plus masks, balaclavas and gloves, officers said.
A YouTube video had reportedly been posted showing a Snapchat broadcast of the grandmother being harassed, abused and threatened by members of the rival gang.
The defendants said they were on their way to make a music video and the weapons they had were simply props.
Detective Superintendent Adam Lowe said: "The lyrics referenced several real and often violent events.
"Their aim was purely to glorify gangs and violence.
"Despite what the gangs may claim, there is a clear link, as in this case, to violence.
"There is no doubt the five defendants that day were in the process of setting out to cause some very serious harm to their rivals.
"They equipped themselves with huge knives and I am sure there would have been some life-changing injuries inflicted or worse had the police not intervened.
"The evidence was overwhelming - they were literally caught red-handed - and they had no option but to plead guilty."
The Met has built up a database of more than 1,400 videos to use as an intelligence tool as the force tries to tackle an increase in killings and other violent crime, with more than 60 murder investigations launched already this year.
YouTube has deleted just over half of the music videos Scotland Yard has asked to be taken down because they incite violence, according to police figures.