Jenny McGee, who cared for the Prime Minister in intensive care at St Thomas’ Hospital in central London, told how she found the Prime Minister in April 2020 when she arrived at work.
She told a Channel 4 documentary: “All around him there was lots and lots of sick patients, some of whom were dying.
“I remember seeing him and thinking he looked very, very unwell.
“He was a different colour really.
“It’s so surreal, that’s the Prime Minister. They are very complicated patients to look after and we just didn’t know what was going to happen.”
In the documentary, The Year Britain Stopped, to be broadcast on May 24, she said that when she looks back on her period with Mr Johnson she thinks it was a “weird” time.
Ms McGee, who is originally from New Zealand, said she had been asked to take part in a “clap for carers” event at a garden party at Downing Street last July.
She and another nurse had been invited along by the Prime Minister to celebrate 72 years of the NHS.
After his release from hospital, Mr Johnson had praised Ms McGee and nurse Luis Pitarma, saying: “The reason in the end my body did start to get enough oxygen was because for every second of the night, they were watching.”
Ms McGee said of the request to join the clap event: “It would have been a really good photo opportunity.
“You know, kind of like Boris and his NHS friends, but I wanted to stay out of it.
“Lots of nurses felt that the Government hadn’t led very effectively, the indecisiveness, so many mixed messages.
“It was just very upsetting.
“Yes, we have put ourselves on the line and we have worked so incredibly hard, and there’s a lot of talk about how we’re all heroes and all that sort of stuff.
“But at the same time, I’m just not sure if I can do it.
“I don’t know how much more I’ve got to give to the NHS.
“We’re not getting the respect and now pay that we deserve.
“I’m just sick of it.
“So I’ve handed in my resignation.”
Later in the documentary, Ms McGee described working at the hospital in the run-up to the festive period.
“Leading up to Christmas, I could just not believe what I was seeing, it was just a cesspool of Covid,” she said.
“And then a whole lot of new patients come in. It was an absolute s**tshow to be honest.
“At that point, I don’t know how to describe the horrendousness of what we were going through.”
In a statement released on Tuesday through Guy’s and St Thomas’ NHS Foundation Trust, Ms McGee said: “After the toughest year of my nursing career, I’m taking a step back from the NHS but hope to return in the future.
“I’m excited to start a nursing contract in the Caribbean, before a holiday back home in New Zealand later in the year.
“I’m so proud to have worked at St Thomas’ Hospital and to have been part of such a fantastic team.”
A No 10 spokesperson said: “Our NHS staff have gone above and beyond over the past year and this Government will do everything in our power to support them.
“We are extremely grateful for the care NHS staff have provided throughout the pandemic in particular.
“That is why they have been exempted from the public sector wide pay freeze implemented as a result of the difficult economic situation created by the pandemic.
“At the same time we have invested £30 million to support staff mental health and are expanding the number of places available for domestic students at medical schools in England to continue expanding our workforce.”
Labour leader Sir Keir Starmer said Ms McGee’s decision was a “devastating indictment of Boris Johnson’s approach to the people who put their lives on the line for him and our whole country”.
Pat Cullen, acting general secretary and chief executive of the Royal College of Nursing, said: “There are already tens of thousands of nursing vacancies and we continue to warn of an exodus from the profession if the Government does not demonstrate its respect by giving nurses a fair pay rise for the skilled work they do.”
Unison head of health Sara Gorton said: “Many more experienced NHS staff could quit unless the Prime Minister sees sense over pay.
“The Scottish government has found the cash to give its health workers a decent rise.
“It’s high time NHS workers across the rest of the UK received the increase they deserve too.”