The Prime Minister, 55, issued a short statement on Saturday hailing the medics as he prepared to spend his seventh night at St Thomas’ Hospital in central London, reports the Metro newspaper.
“I can’t thank them enough. I owe them my life,” he said.
Earlier on Saturday, the Downing Street had said that Johnson was now able to take short walks as he continued his recovery from a severe case of COVID-19.
The Prime Minister was making “good progress” and has been boosted by daily updates from pregnant fiancee Carrie Symonds along with thousands of cards from well-wishers, it added.
However, there has been no update on when he was likely to be discharged.
Aides reportedly expect him to be off for a month recuperating, with Foreign Secretary Dominic Raab deputising in Johnson’s absence.
Johnson was first admitted to hospital on April 5 on the advice of his doctor, amid concerns that he was still suffering coronavirus symptoms after testing positive on March 27, said the Metro newspaper.
It was initially said to be only as a “precautionary” measure and he was reportedly issuing instructions and working on his ministerial red boxes from his sick bed on April 6.
But his condition rapidly deteriorated throughout that afternoon into the evening and he was rushed to intensive care.
He was moved to a general ward two days later.
The news comes as the number of confirmed coronavirus cases in the UK has increased to 79,885, with 9,892 deaths amid an ongoing national lockdown.