Alfie Evans, the 23-month-old toddler at the centre of a High Court legal battle, has died, nearly a week after his life support was withdrawn.
The boy from Merseyside, who had a degenerative brain condition, died at 02:30 BST, his father Tom Evans said.
On Facebook he wrote: “My gladiator lay down his shield and gained his wings… absolutely heartbroken.”
Alfie’s parents lost legal challenges against a High Court ruling allowing the hospital to withdraw ventilation.
The boy had his life support withdrawn on Monday after being in a semi-vegetative state for more than a year.
Mr Evans and Alfie’s mother Kate James’s legal campaign attracted widespread media attention and saw them clash with doctors over the child’s treatment.
Alfie, who was born in May 2016, was first admitted to Alder Hey Children’s Hospital in Liverpool the following December after suffering seizures, and had been a patient at the hospital ever since.
The parents, who lived in Bootle, wanted to fly the toddler to a hospital in Italy for treatment, but this was rejected by doctors who said continuing treatment was “not in Alfie’s best interests”.
The hospital said scans showed “catastrophic degradation of his brain tissue” and that further treatment was not only “futile” but also “unkind and inhumane”.
The court battle between the parents and medical staff lasted for four months.
The couple heavily criticised medical staff, with Mr Evans suggesting his son was a “prisoner” at the hospital and had been misdiagnosed.