A defendant in court was critically injured when he doused himself with a noxious substance while in the dock.
A female dock officer was also injured but did not need hospital treatment after the incident at Inner London crown court on Monday.
According to the BBC, the defendant, Marc Marshall, 54, had just been sentenced for fraud offences when the incident happened. Marshall was reported to have been carrying a metal water bottle, and CCTV footage was said to have shown him sipping from it as he went through security.
A Met police spokesman said: “Police were called to court 10, Inner London crown court, at 12.01pm on Monday 29 April following reports of a serious assault. Officers, London ambulance service and London air ambulance attended and a male aged in his 50s was found to have doused himself with a noxious substance.
“He has been taken to hospital for treatment of his injuries. His condition is critical. A female dock officer was also injured by some of the substance. Her injuries are not believed to be serious and she did not require hospital treatment.”
A HM Courts and Tribunals Service spokesman told the BBC it would be “urgently investigating” the circumstances surrounding the incident.