A man has been arrested on suspicion of attempted murder after a female Serco prisoner custody officer was seriously assaulted by a male prisoner at Blackfriars Crown Court.
The officer, believed to be in her 50s, was left in a critical condition after she was attacked while escorting the prisoner between the court and a waiting van parked in the yard in south-east London.
London's Air Ambulance attended and the victim was treated at the scene before being taken to an east London hospital where she remains.
A 22-year-old man was arrested on suspicion of attempted murder and taken to a south London police station for questioning.
Metropolitan Police said next of kin have been informed of the incident.
Anyone with information that could assist the investigation is asked to call police on 020 8721 4054 or call Crimestoppers anonymously on 0800 555 111.