Stunned witnesses heard one of six victims of a mass attack in east London scream "I can't see" as he writhed in pain outside one of the UK's busiest train stations.
On Saturday (23 September) just before 8pm police say reported that a gang of males sprayed what is believed to be a "noxious substance" close to Stratford Westfield shopping centre.
One witness said that one group of males in balaclavas sprayed the substance from Lucozade bottles.
In total there has been six reported injured, including facial injuries, with one of the victims believed to be a homeless man who ran for help into a Burger King.
The incident took place close to a bus shelter outside Stratford train station, with police and paramedics seen treating injured victims inside the station.
Witnesses say that an argument had taken place between two groups of males before the attack, with some saying that the victims were a group of West Ham supporters.
Earlier in the day West Ham had played fierce rivals Tottenham Hotspur in the London Stadium, in the nearby Olympic Park.
Police have not revealed the exact substance that was used but say they have arrested a 15-year-old boy on suspicion of causing grievous bodily harm in connection with the incident.
Burger King assistant manager Hossen, 28, said that he saw a victim and his friend run into the fast food outlet's bathroom "to wash acid off his face".
He said: "There were cuts around his eyes and he was trying to chuck water into them."
Police cordons were put in place on Saturday night while victims were being treated.
One man James Turvey, 18, said he was sprayed as he ran to help a friend, he said: "We were in McDonald's and, as we got outside, my mate was surrounded by about ten guys.
"They circled him and started punching him. People ran to help him and the gang put on balaclavas, got out Lucozade bottles and started spraying everyone. It was horrific.
"My mate has been rushed to hospital. I don't know how he's doing. I don't know why they did it. They just picked on us."
A statement from London's Metropolitan Police read: "Police were called just before 8pm on Saturday, 23 September to the area around Stratford Shopping Centre to reports of a group of males spraying what is believed to be a noxious substance.
"London Ambulance Service and London Fire Brigade have attended.
"A number of people have been reported injured at different locations - believed to be six people. We await further details.
"One male has been arrested on suspicion of GBH. Officers remain on scene. A cordon is in place. Enquiries continue."