U.K. Prime Minister Boris Johnson has left hospital after a week-long stay due to the coronavirus.

Johnson, who has been battling COVID-19 for more than two weeks, first entered hospital on April 5 and was admitted to intensive care one day later. He spent three nights in the ICU, before being released back into the regular hospital ward on April 9.

Downing Street has said that although Johnson was discharged from hospital Sunday morning, he will not immediately go back to work, and will continue his recovery at his country residence, Chequers.

In a video posted to Twitter Sunday afternoon, Johnson suggested that his coronavirus battle was, at one point, extremely serious. He began: “I have today left hospital after a week in which the NHS saved my life, no question.”

“It’s hard to find words to express my debt,” he continued, before thanking the public for socially isolating over the Easter long weekend in the U.K. before turning his attention again to the NHS, which has been under-funded by the Conservative government for a number of years.

“In the last seven days, I have of course seen the pressure the NHS is under. I have seen the personal courage, not just of the doctors and nurses, but everyone…who have kept putting themselves in harm’s way, kept risking this deadly virus. It’s thanks to that courage, that devotion, that duty and that love that our NHS has been unbeatable.”

Johnson paid thanks to “utterly brilliant” doctors who took “crucial decisions a few days ago” to save his life, personally naming a number of healthcare workers and nurses who attended to him, including two nurses originating from New Zealand and Portugal. “We will win because our NHS is the beating heart of this country. It is the best of this country; it is unconquerable and it is powered by love.”

The 55-year-old Johnson is the first major world leader to have revealed a coronavirus diagnosis.

It is hard to find the words to express my debt to the NHS for saving my life. The efforts of millions of people across this country to stay home are worth it. Together we will overcome this challenge, as we have overcome so many challenges in the past. #StayHomeSaveLives pic.twitter.com/HK7Ch8BMB5 — Boris Johnson #StayHomeSaveLives (@BorisJohnson) April 12, 2020

Johnson’s pregnant fiancée Carrie Symonds also took to Twitter Sunday afternoon to thank the NHS, which treated Johnson at St. Thomas’s Hospital in London. “I will never, ever be able to repay you and I will never stop thanking you,” said Symonds, who revealed last week that she, too, had been experiencing coronavirus symptoms, though hadn’t been tested.

It was first announced that Johnson had contracted COVID-19 on March 27, and though he had been working from his residence, a persisting cough and fever prompted his admission to hospital.

According to the latest figures, the U.K.’s death toll from coronavirus stands at 10,612, while there are 84,279 cases. The first death in the country was recorded on March 5.

On April 10, the U.K. recorded 980 hospital deaths in a single day, surpassing both Italy and Spain’s most fatal days, which were 969 and 950, respectively, according to the BBC.

Unlike other European countries, which were quick to enact lockdowns and gatherings bans, the U.K. government was initially slowly to institute such public health measures and only placed the country in lockdown on March 23. It has struggled in recent weeks to convey the seriousness of the pandemic to the public.

On Sunday, Jeremy Farrar, a senior scientific adviser to the government, said the U.K. could be the worst affected country in Europe.