The mother of a baby whose death has thrown doubt on whether the NHS's out-of-hours helpline can identify when children have potentially deadly illnesses has described the whole situation as "soul-destroying".
Melissa Mead, 29, of Penryn in Cornwall, was speaking after an NHS England report found that 16 mistakes had contributed to the death of her 12-month-old son William.
He died from sepsis as a result of a chest infection on December 14 2014 but could have been saved if a 111 call handler, who spoke to Mrs Mead, had realised the gravity of his illness.
The report also states that a system used by the hotline, which includes a box-ticking questionnaire used by staff who do not have medical training, is not "sensitive" enough to identify when children are deteriorating because of the deadly inflammatory condition sepsis, according to the Daily Mail.
Stating that her 111 call "was not recognised as a complex call", Mrs Mead told ITV's Good Morning Britain (GMB): "We did what we were told to do. We followed their guidance and we went to the doctors. We trusted their guidance and reassurance on multiple occasions.
"We rang 111 because we were concerned and at the time we knew no different so we listened to the advice given and heeded that advice. We were let down."
GPs - who saw William six times in the months leading up to his death - failed to look for signs of sepsis and give him potentially life-saving antibiotics. They also missed the chest infection which contributed to his death.
The report said doctors were under "constant pressure" not to prescribe antibiotics, even when they believed children needed them, and they were also loath to refer people to A&E units unless "absolutely necessary" because of pressures of patient numbers.
According to the report, doctors working out of hours were also unable to access patients' medical records, the Mail said.
It concluded that a "deteriorating paediatric patient" like William was "not easily identified through the structured questioning", called NHS Pathways, used by the 111 call handlers.
Mrs Mead's 111 call was poorly dealt with by an adviser who would have had no more than a few weeks' training, the Mail said, and who failed to notice the "abnormal behaviour" his mother described.
Even if used properly, the 111 system was "not sensitive enough" to pick up William's illness, a "root cause" in his death, the report found.
Breaking down in tears as she cradled a teddy bear containing William's ashes, she told GMB: "William made parenting the best job in the world. He made love easy. He made everything wonderful. He was so happy and we miss him terribly."
Mrs Mead said she hoped that throwing a spotlight on William's treatment will improve the service because the situation must not be allowed to remain where parents do not trust the helpline service.
Lindsay Scott, of NHS England, apologised and told GMB that the service had let Mr and Mrs Mead down.
She said: "It should not have done. We regret that very much and have apologised to Melissa for that."
She said there had been a "lack of probing questions" and a failure to identify this as "a complex situation".