A prison custody officer who was assaulted at a crown court has died.
Lorraine Barwell, 54, who worked for Serco, was attacked on Monday as she escorted a prisoner from London's Blackfriars Crown Court to a waiting van.
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.
Friends and family paid tribute to her on her daughter Louise Barwell's Facebook page.
Vera Rothon, Ms Barwell's mother, said: "RIP Lorraine my first born baby. Love you always xxxxx", while Sasha Elillot added: "May you shine very bright with the angels."
Margaret Monreale Prime wrote: "Louise, to you and the rest of your family my heart goes out to you all. A grafter with attitude, your mum," while a poster named Unique Becks said: "RIP Lorraine ... such a loving caring, dedicated nanny and mum ... gonna miss you having a go at me and Louise for some reason or other lol ... Good night and sleep tight."
Ms Barwell was an experienced prison custody officer and had worked for the services company Serco for more than 10 years.
Close colleague Oscar Garcia-Villaverde 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, Serco's group chief executive, added that Ms Barwell was a "highly respected" member of staff.
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."
He added: "Clearly over the coming weeks and months not only will the police be doing a major investigation, I presume the Ministry of Justice will be doing an investigation, and of course we in Serco will want to get to the bottom in a forensic way of what went wrong."
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 justice services trade union, Community, said it will hold urgent talks with Serco on Monday.
Adrian Axtell, national officer for Community said: "Our thoughts are with the family, friends and colleagues of Lorraine Barwell. This despicable crime should give everybody pause for thought about the dangers that prison custody officers can potentially face on a day-to-day basis.
"We will begin discussions with Serco on Monday to work together and respond appropriately to this tragic incident. However, safety of staff should be an issue for government not just the contract operators.
"An urgent review of the security of staff must be conducted. Appropriate risk assessments need to be carried out, including a review of staffing levels. There should never be a chance for this kind of incident to be repeated. As the union representing court escort staff we want safe operating solutions for all our members, regardless of which government contract they are working on."
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."