LONDON — Capt. Sir Tom Moore, the centenarian who raised $45 million for Britain's National Health Service by shuffling laps across his garden with the aid of a walker during the nationwide coronavirus lockdown last year, has died at the age of 100, his family announced Tuesday.

The medal-bedecked veteran, who was knighted last year by Queen Elizabeth II for his jaw-dropping charitable campaign, had spent the past few weeks being treated for pneumonia and tested positive for the coronavirus last week.

“Captain Tom,” as he was known to all, stole the hearts of the British, who saw in him a can-do, big-hearted living link to yesteryear, the embodiment of the “keep calm and carry on” spirit that got the country through the Blitz in the early days of World War II.

During his slow-motion fundraising marathon, often outfitted in a blue blazer and regimental tie, he would urge his patrons to always remember, “Tomorrow will be a good day.”

Moore was also a willing performer and a great quote for the newspapers and TV cameras.

“One small soul like me won’t make much difference,” he said in his first television interview. But he did.

Footage from April 2020 shows how Capt. Sir Tom Moore raised almost $45 million for Britain’s National Health Service. He died Feb. 2 at age 100. (Reuters)

The morning he was to be knighted by the queen at Windsor Castle, Moore wrote on his Twitter account, “Ready and raring to go for what is a very special day.”

A few hours later, he joked with a camera crew he would not, alas, kneel before the queen — “because if I did, I’ll never get up again.”

His family said they were grateful to be with him at the end — some of them on FaceTime and some by his bedside at the hospital. In Britain, as elsewhere, coronavirus patients have tended to be isolated from their families and support networks, to limit the spread of the virus.

“The last year of our father’s life was nothing short of remarkable,” Moore’s daughters, Hannah Ingram-Moore and Lucy Teixeira, wrote in a statement. “He was rejuvenated and experienced things he’d only ever dreamed of.”

They also thanked the NHS: “They have been unfalteringly professional, kind and compassionate and have given us many more years with him than we ever would have imagined.”

Moore was believed to have not been vaccinated against the virus because of the medication he was receiving for the pneumonia, British media outlets reported.

It is a myth that the British are a nation of stiff upper lips. They embraced Captain Tom as they embrace nostalgia. He appeared on the scene right when needed most, as the country — alongside the rest of the world — faced a scary new virus that shuttered shops, schools and pubs. The highest death toll from the pandemic was Moore’s generation.

“At times of crisis, a nation needs hope and heroes,” the BBC reported.

The queen was one of the first to publicly mourn his death.

“Her Majesty very much enjoyed meeting Captain Sir Tom and his family at Windsor last year. Her thoughts and those of the Royal Family are with them,” the royal family’s official Twitter account tweeted.

Prince William, her grandson, earlier called Captain Tom “a one-man fundraising machine.”

Prime Minister Boris Johnson said Moore “was a hero in the truest sense of the word. In the dark days of the Second World War, he fought for freedom, and in the face of the country’s deepest postwar crisis, he united us all, he cheered us all up, and he embodied the triumph of the human spirit.”

The NHS applauded the veteran for his contribution.

Some have pointed out that Moore’s private campaign was so important because the health service had been starved for public funds over the past decade. At the outset of the pandemic, hospitals faced a crippling lack of supplies. Some health workers wore trash bags, as there wasn’t enough personal protective equipment to go around.

“They’re all being so brave. Every day, they’re putting themselves in danger of this unseen enemy that we’ve got at the moment,” Moore said of doctors and nurses in an interview with Sky News Australia last year.

Moore served as a young officer in 146th Royal Armored Corps, first in India and then Burma, joining what the BBC called “the bruised and bloodied forgotten army, which was suffering from disease and low morale, fighting in the world’s least hospitable terrain, with impenetrable jungle, poisonous snakes and hot lashing rain for six months of every year.”

The broadcaster reported, “Much of the fighting was done hand-to-hand, with no quarter given on either side.”

Moore survived the war, served in Britain’s peacetime army, retired and then worked as a salesman for a roofing company.

His garden odyssey — and unexpected rise to stardom — began in April, when he sought to raise 1,000 pounds (about $1,370) for the NHS by walking his 82-foot-long garden path back and forth 100 times, using his walker for support.

He wanted to complete the journey, which he broke down into short ambles, ahead of his 100th birthday on April 30.

As public interest in his fundraiser grew, so did the pot of donations.

Just 24 hours after Moore started walking, he had raised the equivalent of $8,750. As money poured in, Moore’s fundraising page crashed repeatedly.

He completed his final lap two weeks ahead of schedule — an event that was live-streamed by the BBC as the figure reached $15 million. Afterward, donations continued to climb.

Moore was treated on his 100th birthday in April to a Royal Air Force flyby above his home in Bedfordshire, 50 miles north of London. The Royal Mail service issued a special postmark, stamping letters with his name and birth date. Children and fans sent him more than 150,000 birthday cards, and street art of his image appeared around the country.

In a letter of his own on his birthday, addressed to a “remarkable” public, Moore wrote: “The past three weeks have put a spring back in my step. I have renewed purpose and have thoroughly enjoyed every second of this exciting adventure, but I can’t keep walking forever.”

Karla Adam contributed to this report.