A nurse broke down in tears as she told an inquest how she tried to help a dying boy whose serious illness had not been picked up earlier by medical staff.
Katherine Ramsden told the hearing that six-year-old Jack Adcock should never have been sent to her ward - a general paediatric ward - in the first place.
The 26-year-old broke down several times while giving her evidence, after which she turned to the youngster's parents, Nicky and Vic, and said: "I just want to say I'm really sorry. I'll never forget your little boy."
Despite being seriously ill with pneumonia, Jack, who had initially been seen on the children's admissions unit at Leicester Royal Infirmary, was transferred to Ward 28 rather than intensive care.
Within an hour of being admitted to the ward, the youngster went into cardiac arrest.
Miss Ramsden told the hearing: "Jack was very, very, very sick by the time he came to me. To have a cardiac arrest an hour after arrival to a general paediatric ward is not acceptable."
Miss Ramsden said she was not happy with the information she received about Jack and his condition by the nurse who transferred him to Ward 28.
She said she noticed there was a blue tinge around his lips and that his hands and feet were very cold.
"I recognised that Jack was not how I would want a child to be on my admission, but I did not realise the outcome that was about to happen," Miss Ramsden told the court.
Jack, of Glen Parva, was admitted to the hospital at about 10am on February 18, 2011, suffering from sickness and diarrhoea.
He died shortly after 8pm that evening.
The inquest, which started on Monday, previously heard Jack was mistaken for another boy who had a 'do not resuscitate' order placed on him.
Dr Hadiza Bawa-Garba, who had been monitoring Jack throughout the day, told the court on Tuesday that she interrupted attempts to resuscitate him after getting him mixed up with the other child.
When she realised her mistake, resuscitation was started again - but Jack could not be saved.
At the hearing today, Miss Ramsden said she was in the room when Dr Bawa-Garba called off the resuscitation.
"When it was announced that Jack was not for resuscitation I shouted - to the whole room, not to anyone in particular - that that was not handed over to me."
Two doctors and a sister who were in the room at the time told the court they had not heard this. However, they all said the room was full of people, very noisy and "quite chaotic".
The inquest also heard from Dr Esaivani Archary, who was on the resuscitation team, earlier today.
She was asked if she believed Jack would have survived had the initial resuscitation attempt not been called off.
"I'm not an expert but I know that when I arrived Jack was already in cardiac arrest," she said. "Jack was already in a very bad position. On that initial assessment, prognosis is poor."
Earlier this morning, the inquest heard from Dr Stephen O'Riordan, who was on call on the children's admissions unit that day. He told the court he arrived at about 4pm, but was not given any information about Jack from Dr Bawa-Garba that gave him cause for concern and so did not go to see him. He said this was standard practice.
"If the full picture had been explained to me, of course I would have seen this child," he said. "There's a clear communication failure here."
When asked by coroner Catherine Mason what he would have done if Jack had been referred to him, he said that, after carrying out tests, "I would have at least asked for an ICU (intensive care unit) consultant to come down to see the child straight away, with a view to transferring him to ICU."
The inquest continues.
