An American professor who has offered to treat Charlie Gard is due to examine him next week.

Michio Hirano, a professor of neurology at the Columbia University Medical Center in New York, is scheduled to visit Great Ormond Street Hospital, on July 17 and 18, to discuss the case with the specialists treating Charlie.

The terminally-ill baby's parents, Chris Gard and Connie Yates, want the judge to rule the 11-month-old, who suffers from a rare genetic condition and has brain damage, should be allowed to undergo a therapy trial overseen by Dr Hirano in New York.

Specialists at Great Ormond Street Hospital in London, where Charlie is being cared for, say the therapy is experimental and will not help and life support treatment should stop.

Dr Hirano gave evidence, via a link from New York, on July 13, that there is new evidence and the baby boy's parents 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 carry out a fresh analysis of their case.

The judge said he wanted to hear what Dr Hirano believes has changed since he gave his ruling in April.

Dr Hirano said he has clinical data which was not available in April and he still believes the therapy is ''worth trying'' - estimating a 10% chance of improvement in muscle strength and a ''small but significant'' improvement in brain function.