Charlie Gard's parents reacted furiously when a barrister representing Great Ormond Street Hospital broke the news that a report on a new scan on the terminally-ill baby made for "sad reading".
His mother, Connie Yates, burst into tears and his father, Chris Gard, yelled "evil" after Katie Gollop QC on Friday told a judge analysing the latest stage of a legal battle over treatment what doctors thought of fresh scan results.
Mr Justice Francis was analysing preliminary issues at a hearing in the Family Division of the High Court in London on Friday prior to scheduled trial on Monday.
Mr Gard and Ms Yates want the judge to rule their 11-month-old son, who suffers from a rare genetic condition and has brain damage, should be allowed to undergo a therapy trial overseen by a specialist in New York.
Doctors at Great Ormond Street Hospital in London, where Charlie is being cared for, say the therapy is experimental and will not help.
They say life support treatment should stop.
Earlier this week the American specialist, Michio Hirano, a professor of neurology at Columbia University Medical Centre in New York, travelled to London to examine Charlie for the first time and discuss the case with Great Ormond Street doctors.
Ms Gollop told the judge that doctors had produced a report on the newest scan and said: "It makes for sad reading."
Ms Yates began to cry and said: "We haven't even read it."
Mr Gard yelled "evil" and added: "I'm not f****** listening to this biased shit anymore."
The couple then stormed out of court.
Ms Gollop apologised.
"Almost all the medical evidence in this case makes for sad reading," she told the judge.
"I'm very sorry. I didn't mean to cause distress."
Barrister Grant Armstrong, who represents the couple, said Ms Gollop should not have broken the news about the scan before Charlie's parents had read the report.
Charlie's parents, who are in their 30s and come from Bedfont, west London, have already lost battles in the High Court, Court of Appeal and Supreme Court in London.
They have also failed to persuade European Court of Human Rights judges to intervene.
But the couple say there is new evidence and want Mr Justice Francis, who in April ruled in favour of Great Ormond Street and said Charlie should be allowed to die with dignity, to change his mind.
The judge is due to consider their latest claims in detail next week before making a decision.
Mr Justice Francis has told Charlie's parents he will not re-run the case but will consider any ''new material''.
Lawyers say they will examine the latest expert reports, and data from fresh scans, over the weekend.
Mr Armstrong had earlier told the judge a ''range of opinions'' had been expressed when experts gathered a few days ago.
He said he believed at least one specialist had "something new".
But Ms Gollop said: ''We don't yet have any of this apparent new evidence.''
Lawyers said Dr Hirano and Charlie's parents could give evidence at next week's hearing.