Terminally-ill baby Charlie Gard must continue to receive life support until judges make a ruling on whether he should undergo a trial treatment.
Parents Chris Gard and Connie Yates have launched a final legal challenge at the European Court of Human Rights after a Supreme Court challenge failed.
European judges said doctors were required to keep the 10-month-old alive until they had passed judgement.
Specialists at Great Ormond Street believe he has no chance of survival.
Charlie has been in intensive care in hospital since October last year.
His doctors said he cannot hear, move, cry or swallow and that his lungs only go up and down because he is on a machine that does it for him.
Judges in Strasbourg, France, had previously ruled an interim measure to keep him alive should remain in place until midnight on 19 June.
The extension lasts until a final ruling is made.
A spokesperson said they “will treat the application with the utmost urgency” but have not indicated when the final judgement will be made.