A female security guard is critically ill in hospital after she was assaulted by a prisoner at Blackfriars Crown Court.

Police say the prisoner custody officer, employed by private firm Serco, was seriously assaulted by a male prisoner.

The guard - believed to be in her 50s - was attacked at around 1.30pm yesterday as she escorted the prisoner between the court and a waiting van which was parked inside the court yard.

London's Air Ambulance was called and the victim was treated at the scene before being taken to an east London hospital, where she was in a critical condition.

A man aged 22 has been arrested on suspicion of attempted murder and remains in custody at a south London police station.

Anyone with information is asked to call the incident room on 020 8721 4054, or Crimestoppers anonymously on 0800 555 111.