A teenager has been arrested following five attacks in north-east London which involved corrosive substances being thrown in peoples' faces.
They all happened within 90 minutes in Hackney, Stoke Newington and Islington on Thursday night and detectives are treating them as linked.
The attacks began at 10.25pm on Thursday in Hackney Road.
The teenage male is being held at an east London police station on suspicion of grievous bodily harm and robbery.
The victims were taken to hospital, with one of them suffering "life-changing injuries".
One 32-year-old man on a moped was left with facial injuries after a moped, with two male riders, pulled up alongside him in Hackney at about 10.25pm.
The pair threw a corrosive substance in the victim's face, say police, with one stealing his moped and the other driving away on the vehicle they arrived on.
The Met said it was awaiting an update on the extent of the victim's injuries.
At 10.49pm a man was reported to have had a corrosive substance thrown in his face by two men on a moped in Islington.
Following this incident, at 11.05pm a corrosive substance was reported to have been thrown in the face of a person by two men on a moped in Shoreditch High Street.
The victim has been taken to hospital, although police said the injuries were not believed to be life threatening or life changing.
At 11.18pm police received reports of a robbery in Cazenove Road, Stoke Newington, where a corrosive substance had been thrown.
Officers attended and found a man suffering from facial injuries that have been described as life changing.
In a fourth incident, in Chatsworth Road, Clapton, at about 11.37pm, a man on a moped was in traffic when two men on a moped pulled up alongside him and sprayed liquid in his face, before stealing his vehicle.
The victim has been taken to an east London hospital.
The Met said enquiries were ongoing.