Serco security guard Lorraine Barwell dies after attack outside Blackfriars Crown Court

Lorraine Barwell was 54 and worked for Serco.

She was assaulted as she escorted a prisoner between the court and a waiting van parked in the courtyard on Monday.

An air ambulance was called and she was treated at the scene before being taken to an east London hospital, but Scotland Yard said today she has died.

It was reported her family agreed to turn off her life support system after doctors told them there was no chance of recovery.

Ms Barwell, a mother of two and a grandmother, is the first prison custody officer to die in the line of duty, the Ministry of Justice said.

Humphrey Burke, 22, of no fixed address, appeared at Camberwell Green Magistrates' Court on Wednesday charged with GBH and was remanded to appear at the Old Bailey on July 15.

Oscar Garcia-Villaverde, a close colleague of Ms Barwell's at Serco, said: "Everyone who worked with Lorraine, who was affectionately known as Rocky, is absolutely devastated by what has happened.

"Lorraine was really well-liked and she had many friends here; we will all miss her dreadfully. Our thoughts are with her family."

Rupert Soames, the company's group chief executive, added that Ms Barwell was an experienced officer who was "highly respected".

He said: "We are all appalled and saddened by the dreadful news that Lorraine has died of her injuries, and our hearts go out to her family and many friends.

"They are in our thoughts, and on behalf of everyone at Serco I want to send them our sincerest sympathies and condolences. We will do everything we can to support them at this very difficult time.

"Lorraine was a brave and experienced prisoner custody officer who was a popular and highly-respected member of our team, and had worked for Serco for over 10 years. She will be sorely missed by everyone who worked with her.

"The team who escort and look after prisoners as they travel to and from court perform an important and difficult public service, and we should all appreciate the work they do."

Mr Soames said Serco deals with around 20,000 prisoner movements every month in London and East Anglia alone, and that it was the first tragedy of its kind in more than 25 years.

He told Sky News that procedures for transporting prisoners are "well developed" and depend on an assessment of the individual being moved.

Prisoners are handcuffed while being moved from one location to another, he said, while in certain circumstances prisoners may be accompanied by "multiple experienced officers", and he understood that this was the case on Monday.

He said: "It was not just Lorraine who was there, there were a number of very experienced officers and the person in question was under restraint at the time."

Justice secretary Michael Gove said: "I was shocked to hear of the tragic death of Lorraine Barwell. No words can express the devastating effect this will have on her family and friends and my deepest sympathies are with them at this difficult time.

"Lorraine Barwell was a courageous and dedicated prisoner custody officer who delivered a vital public service for more than a decade. She, like thousands of prison officers across the country, worked hard in challenging circumstances to keep the public safe.

"My department will provide every assistance to the police as they investigate this incident."

The POA, the Professional Trades Union for Prison, Correctional and Secure Psychiatric Workers, added that the thoughts of all its members are with the family, friends and colleagues of Ms Barwell.

It said: "Although not a member of the POA, this unspeakable crime should serve to remind the public and politicians of the violent and unpredictable nature of the criminal justice workplace.

"This is not about public good, private bad, or vice versa, but a stark illustration that staff within the criminal justice system care for and control violent criminals 24 hours a day every day of the year in the essential protection of the public."