Police have arrested a third person in connection with a stabbing outside Richmond College in Twickenham.
A 17-year-old boy, who cannot be named for legal reasons, was arrested on suspicion of GBH on Thursday and remains in custody.
Police were called by London Ambulance Service at 12.35pm on Wednesday to Egerton Road following reports of a stabbing.
A 17-year-old student at the college was taken to a central London hospital, where he remains in a stable condition.
Two other 17-year-old boys were arrested on suspicion of GBH on Wednesday and have since been bailed until a date in July.
On Wednesday, a Richmond College spokesman said: “On Wednesday, May 14, there was an incident in Court Way, Twickenham.
“One of the college’s students was involved and sustained injuries to his abdomen and was taken to hospital.
“The matter is being handled by the Metropolitan Police.”