An innocent bystander has been shot in the chest as a gang filming a music video brawled with rival thugs, police say.
The 32-year-old woman is fighting for her life after being caught in the crossfire outside a pub at about 9pm on Sunday.
Detective Inspector Matt Webb appealed for witnesses saying around ten people were on Broadway Market – which meets Westgate Road - about ten minutes before the incident.
He said: “It appears the group were being filmed for the purposes of a music video, with professional looking camera equipment.
“It then appears that the group have become involved in an altercation with another group of people who arrived at the scene.
"During this incident one of the groups produced and discharged a firearm - both groups then fled the scene.
“The victim was an innocent bystander and left seriously injured in the street.”
He added: “Police must work with communities to catch criminals and this incident is an example of how important that is right now.
"Someone knows who did this; I say to those people, please do not help violent criminals by remaining silent."
Dame Cressida is said to have been ''very moved'' by details of the appalling shooting of the innocent victim, understood to have come from outside of London.
Witnesses said they believe the victim had been outside a pub when she was mistakenly shot.
There was a "a lot of blood" as paramedics were seen performing CPR to save her life for around an hour outside a shop.
She was then rushed to an East London hospital where she remains in a life-threatening condition.
A large cordon around Westgate Street and Broadway Market remains in place and forensics officers could be seen combing the scene today.
No arrests have yet been made.
Trident detectives from Specialist Crime North are investigating.