Dr Hilary Jones has opened up about the moment he spoke to Derek Draper on the phone and advised his wife and Good Morning Britain colleague Kate Garraway to call an ambulance.
Speaking to Ben Shephard and Ranvir Singh on Friday's show, he recalled: "I spoke to Kate and Derek and he had been deteriorating, his symptoms weren't typical by any means, and Kate was worried. Of course she calls her colleague at work and very, very happy to help in those situations as I have in the past.
Kate's husband has been in intensive care for nine weeks
"And I spoke to Kate, she was concerned about whether she should call an ambulance and I said, 'Is it possible to speak to Derek?' And I spoke to Derek and I was concerned by the way he was speaking and his breathlessness and I just asked him to do a very simple test, and this is not a diagnostic test, I have to say, for COVID-19.
"All I asked him to do was to hold his breath and see how long he could hold it for without becoming uncomfortable and it was less than 10 seconds and I said to Kate, 'Look, this is the time to call an ambulance, he is breathless, significantly breathless'," he told the presenter and viewers.
"And that's when he was admitted and I've been in touch with her since, and she has been so strong, so supportive of the NHS and everything they've done and they've done a remarkable job but he is still very poorly, and we send our love and support," he added.
Kate appeared on the show for the first time since her husband's diagnosis
Ben later asked Dr Hilary for how long can a healthy person hold their breath for: "He is 52, typically how long should a 52-year-old man be able to hold his breath?"
"You and I and Ranvir we would be able to hold our breath for a minute," Dr Hilary revealed. "Under ten seconds was significantly abnormal, and whilst it's not a diagnostic test in any way it was a reason to send him to hospital straight away."