An eight month old boy being denied “potentially life-saving” treatment at Great Ormond Street would be given it at any hospital in America, a court has heard.

The parents of terminally ill Charlie Gard broke down in tears as they listened to medical evidence relating to his rare genetic condition and what his doctors say is a “vanishingly small” chance of his survival.

But an American doctor who has agreed to attempt a pioneering treatment for his mitochondrial disorder, said that it was “reasonable” to attempt to save his life and if he were in a hospital in the USA his parents would have the option.

Great Ormond Street, where Charlie is currently being treated, have applied to the High Court in for permission to withdraw life support and argue that he should not be taken abroad for treatment as it will prolong his suffering.

His parents, Connie Yates and Chris Gard, who clutched his son’s toy monkey throughout the hearing, disagree and have raised £1.2 million in less than a month to pay for treatment.

The money, which has included donations of £10,000 from Tamara Ecclestone and £40,000 from housewife Helen Barnes who was moved by the family’s plight, will pay for an Air Ambulance to the United States and nucleoside therapy, which the court heard had never been attempted on a human or an animal with Charlie’s condition.