Boris Johnson and his fiancée Carrie Symonds

Doctors were prepared to announce that Prime Minister Boris Johnson had died as he battled coronavirus.

Mr Johnson spent three anxious nights in St Thomas’ in London.

He said medics gave him “litres and litres of oxygen”.

The PM told the Sun on Sunday it was a “tough old moment”.

And if he’d not pulled through, there was a plan in place.

He said: “They had a strategy to deal with a ‘death of Stalin’-type scenario.

“I was not in particularly brilliant shape and I was aware there were contingency plans in place.

“The doctors had all sorts of arrangements for what to do if things went badly wrong.

“They gave me a face mask, so I got litres and litres of oxygen and for a long time I had that and the little nose jobbie.”

Despite all the medical care Mr Johnson, 55, said he “couldn’t understand why I wasn’t getting better”.

His health rapidly deteriorated in days.

The PM said the “indicators kept going in the wrong direction”.

He questioned himself: “How am I going to get out of this?”

Mr Johnson added: “The bad moment came when it was 50-50 whether they were going to have to put a tube down my windpipe.

“That was when it got a bit … they were starting to think about how to handle it presentationally.”