Chris Gard and Connie Yates held back tears as they withdrew their appeal during a London High Court hearing, marking the end of a heartbreaking legal battle that captured international attention.

The couple wished to send their 11-month-old son, who suffers from a rare genetic condition which causes progressive muscle weakness and brain damage,  to the US or Italy for an experimental treatment.

However, their lawyer said on Monday that recent medical tests indicated that Charlie has irreversible muscular damage and that it is too late for the new treatment to be effective.

As the legal battle between Charlie’s parents and the Great Ormond Street Hospital unfolded, Britain's courts, backed by the European Court of Human Rights, refused permission for him to be sent overseas, saying it would prolong his suffering without any realistic chance of improving his condition.

Earlier in July, British Foreign Secretary Boris Johnson told Italian Foreign Minister Angelino Alfano that legal reasons prevented Britain from allowing the child to be treated at the Vatican's Bambino Gesù Children’s Hospital.

The hospital had offered to help Charlie after Pope Francis said treatment should be provided "until the end".

The head of Bambino Gesù's muscular and neurodegenerative illnesses department, Enrico Silvio Bertini, said on Tuesday that it was too late to help Charlie despite the hospital’s efforts.

"Unfortunately, it has emerged that it is impossible to start the experimental therapeutic plan in the light of the clinical evaluation... because of the seriously compromised condition of little Charlie's muscle tissue," he said.

 A judge will decide on Wednesday whether to grant the “last wish” of Charlie’s parents and allow the baby to go home to die.

With ANSA