LONDON — The parents of a terminally ill British baby whose life support is to be withdrawn were in court on Thursday (July 14) to hear new evidence for his possible treatment, in a case that has moved Britain and prompted US President Donald Trump and Pope Francis to intervene.

"If there is important evidence which suggests that I should change my decision then I will change it," Judge Nicholas Francis told the packed courtroom in central London.

Judge Francis previously ruled that life support for 11-month-old Charlie Gard should be withdrawn.

Emotions ran high at the hearing and the boy's parents, Connie Yates and Chris Gard, at one point walked out of the courtroom over a disagreement about what they had said at a hearing in April.

London's Great Ormond Street Hospital, where Charlie Gard is being treated, asked a court to rule on how to proceed last week after the Vatican and the United States offered to help.

Earlier this week, the boy's parents submitted a petition of over 350,000 signatures to the hospital, demanding that they be allowed to take him to America for treatment.

A Vatican-run hospital in Rome has also said treatment may be possible.

But the London hospital has stood by its opinion that Gard's rare form of mitochondrial disease, which causes progressive muscle weakness in the heart and other key organs, is not treatable.

Doctors there believe Gard's brain damage is "severe and irreversible" and have said the baby may be suffering, contradicting his parents.

In evidence presented to the court, Great Ormond Street Hospital said the genetic disorder has left Gard "deprived of his senses" and that he is "without any awareness" as far as doctors can tell.

"He has no quality of life and no real prospect of any quality of life," the hospital said.

But doctors said it was "right to explore" any new evidence and that they were seeking the court's view.

THERAPY TESTED ON MICE 

A doctor appearing from the US by video link, who cannot be named for legal reasons, said there was now clinical data which had not been available in April.

He said a new therapy which had proven effective when tested on mice had a 10 per cent chance of "clinically meaningful success" if tried on Gard.

The US expert said he would be willing to come to London to examine the baby, saying he thought the muscle therapy was "worth trying".

Supporters outside the High Court wore blue hearts and carried placards reading "Save Charlie Gard" and "We have hope". 

"It's murder!" read a hand-written slogan on one woman's t-shirt, with a children's toy monkey similar to one pictured with the baby in her pocket.

At a preliminary hearing on Monday, the baby's father accused the hospital of lying and shouted at the barrister representing the facility: "When are you going to start telling the truth?"

Gard's parents have lost a series of appeals in British courts and at the European Court of Human Rights in Strasbourg and had no further legal recourse.

The case drew international attention last week after the pope expressed his support for the baby's parents, saying he hoped doctors would allow them to "care for their child until the end".

Mr Trump also waded into the debate last week, tweeting that the United States "would be delighted" to help.

The case at London's High Court is due to resume on Friday. AFP