The nurse who was found dead after being duped by a prank call from two Australian radio DJs was reassured on a number of occasions by senior management after the hoax, the chief executive of King Edward VII's Hospital said.
John Lofthouse also said mother-of-two Jacintha Saldanha, 46, was the victim of a "cruel trick", after which senior staff did not blame her and offered her time off and counselling.
Jacintha Saldanha, in a photo released by her family
Writing in reply to MP Keith Vaz, who stated that Ms Saldanha's family needed to know the "full facts" of what happened, Mr Lofthouse said: "Jacintha believed that the call was genuine, and she felt it appropriate to put the call through. We stand by her judgment.
"Following the hoax call, Jacintha was reassured on a number of occasions by senior management that no blame was attached to her actions and that there were no disciplinary issues involved, because she had been the victim of a cruel trick."
The nurse, who is from Bristol, was found hanging in her nurses' quarters by a colleague and a security guard last Friday.
The nurse transferred the DJs, believing they were the Queen and Prince of Wales, to a colleague who described in detail the condition of the Duchess of Cambridge during her hospital stay for severe pregnancy sickness.
Mr Lofthouse said she was offered a range of support after the hoax, including time off, but decided to continue working.
He wrote: "As well as this reassurance, Jacintha was offered a range of further support including time off, the opportunity to return home and counselling from our occupational health service.
"Jacintha said that she would prefer to continue working. Neither ourselves, her friends or family noticed anything to give cause for concern."
Labour MP Mr Vaz, who is campaigning on behalf of the family, had written to Mr Lofthouse, saying: "I have dealt with similar cases in the past and I would agree with the Prime Minister that the family need to get the full facts, from the time she took the call from 2Day FM to the time she was found in her accommodation."
The letter said Ms Saldanha's family would take up the hospital's offer of bereavement counselling and that they had also given the institution a list of questions they wanted answered.
Staff gathered at the hospital today for a private memorial service for Ms Saldanha.
A mass is due to be held for the nurse at London's Westminster Cathedral tomorrow.
The mass will be offered "for the repose of the soul of Jacintha and her grieving family", a spokesman for the Cathedral said.
"We would hope to hold a more formal memorial after the inquest has concluded," he added.
A provisional date of March 26 has been set for the next inquest hearing.
Indian-born Ms Saldanha, whose body was identified by her accountant husband Benedict Barboza, was also found with marks on her wrist, Westminster Coroner's Court in London heard yesterday.
The DJs behind the hoax call - Mel Greig and Michael Christian - have given an emotional account of their reaction to Ms Saldanha's death.
Interviewed on Australian TV networks, the presenters said their prank call to the hospital prompted "a tragic turn of events no-one could have predicted or expected".
Southern Cross Austereo (SCA), the parent company of 2Day FM, has ended the pair's Hot 30 show and suspended prank calls across the company.
Staff at SCA have been forced to move into safe house accommodation and managers have recruited 24-hour bodyguards for their protection, according to reports.
Australian news website news.co.au said police have launched an investigation due to staff receiving death threats, with one letter specifically targeting Mr Christian.
The letter reportedly said there are "bullets out there with your (Mr Christian's) name on" and contained further threats involving a shotgun.
Mr Vaz also wrote to Rhys Holleran, the chief executive of SCA, calling for the full facts.
Mr Holleran replied saying SCA would carry out "a complete review of all of our procedures and processes".
The Australian Communications and Media Authority (Acma) has announced an investigation into the broadcast, he added.
Mr Holleran said SCA has been given a deadline of January 4 to comply with detailed requests for information.
He added: "As we have stated publicly, we are truly sorry for what has happened."
Mr Vaz, in response, invited Mr Holleran to send an apology addressed to Ms Saldanha's husband, which Mr Vaz said he would pass on.
He added that he would be asking Acma make the results of its investigation public.
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