A US doctor who has offered to treat critically ill British baby Charlie Gard has attended a meeting at Great Ormond Street Hospital, to help decide whether the 11-month-old will go to the US for treatment.

Michio Hirano, a professor of neurology at the Columbia University Medical Centre in New York, spent around four and a half hours inside the hospital this afternoon.

Great Ormond Street Hospital said there was an honorary contract in place, meaning that for the duration of the visit Dr Hirano had the same rights as one of the hospital's own clinicians.

He was also given full access to Charlie's medical records, and hospital and clinical facilities, including diagnostic images.

Dr Hirano was also given an opportunity to examine Charlie, according to the hospital.

Meetings between the American neurosurgeon and other medical experts are due to continue tomorrow.

A judge has previously ruled that Charlie's mother, Connie Yates, can be present for the meetings with Dr Hirano.

It has prompted a heated debate about whether the hospital treating the child or his parents should determine his fate.

Charlie's parents are fighting for the right to take the 11-month-old to the US for a therapy trial for his rare genetic condition, overseen by Dr Hirano.

Great Ormond Street Hospital specialists say that treatment will not work, and the little boy's life support should be turned off.

His parents, from Bedfont, west London, have already lost battles in Britain’s High Court, Court of Appeal and Supreme Court.

They also failed to persuade European Court of Human Rights judges to intervene.

Mr Justice Francis has considered the couple's latest claims at preliminary hearings in the Family Division of the High Court in London over the past few days.

He is due to stage further hearings later this month following this week's specialist gathering.