Fresh scans of a seriously ill 20-month-old whose family are fighting a decision to end life support show the boy's brain disease has progressed.
Alfie Evans had already suffered "catastrophic degradation" to his brain from a "relentless" neurological condition, leaving him in a semi-vegetative state.
His medical team, at Alder Hey Children's Hospital in Liverpool, believe to continue life support through ventilation is "unkind, unfair and inhumane".
Mr Justice Anthony Hayden, hearing the hospital's application to end life support at the High Court in Liverpool ordered fresh MRI scans of the boy over the weekend.
Parents Tom Evans, 21, and Kate James, 20, want him to be transferred to a hospital in Rome to undergo further treatment and operations for his condition.
The previous set of scans, taken last August, showed Alfie's brain had reduced by more than 70% of normal size.
Six months on, the latest scans - taken on Friday - showed the disease has now destroyed even more of his brain.
A consultant at Alder Hey, who cannot be named for legal reasons, told the court the latest scans showed further deterioration of the boy's brain.
He said more brain matter had disappeared and the spaces inside Alfie's skull filled with fluid had increased.
Two key parts of his brain, the Thalamus and Basal Ganglia, had also reduced in size to the point that they had almost gone.
The expert continued: "It shows us visibly the destruction of vital structures of the brain which are required for any normal sensory processing.
"Alfie is unaware, in a deep coma, not able to sense, touch, to see or to hear. His clinical impression has not changed over many months."
Both parents sat in court looking down at the desk in front of them during today's hearing. They are not represented by lawyers, but are being supported by around 20 family and friends in court.
Alfie's loved ones maintain he responds to them - but doctors say this is simply the child suffering seizures.
The family, from Liverpool, want their son to be transferred to the Vatican-linked Bambino Gesu Paediatric Hospital in Rome, for treatment which may prolong his life.
Mr Justice Hayden asked the Alder Hey consultant if the Italian approach to the "preservation of life" was different to the "more secular" UK, asking the witness, "why are they wrong?"
The doctor replied: "In my opinion it does not serve the purpose. It is not in Alfie's best interests. If there's no hope for recovery, there's no hope even for stabilisation.
"No hope for any development process. No hope for him to achieve anything you would regard as a meaningful life; to communicate, to learn, even to be able to sense. I don't think we should prolong life.
"Alfie is alive because we are interfering. That's something we must not forget.
"It does not help. It does not cure. It does not make better."
Alfie's father questioned whether "every avenue" had been explored for his son.
The doctor replied: "I honestly believe we have done everything. One can argue we have done more than everything.
"I believe we have explored every avenue. I believe the diagnoses of a relentlessly progressive neurological disease is demonstrated very clearly.
"It's my belief we have done everything possible."
Later, following questions from the judge, a second doctor from Alder Hey described how the removal of ventilation and Alfie's death would be handled.
She said: "It would be managed so that the family are looked after..."
At that point around half a dozen of Alfie's family, including his father, burst into tears and had to leave court.
The hearing continues.