The parents of a baby with a rare disease stormed out of a London court hearing on Thursday as the couple tried to convince a judge to let them take their critically ill child to the United States for medical treatment.

Charlie Gard's parents are challenging the view of the Great Ormond Street Hospital, arguing that treatment abroad is in the best interest of the 11-month-old suffering from a rare genetic condition.

A succession of judges has backed specialists at the hospital who argue experimental treatment in America won't help and may cause suffering for Charlie. The parents hoped to present fresh evidence to alter that view.