Marston Moretaine, UK - The 100-year-old British fundraiser Sir Tom Moore, popularly known as Captain Tom, has died after being taken seriously ill with Covid-19.

In a statement, his daughters Hannah Ingram-Moore and Lucy Teixeira said they were announcing his death with "great sadness."

"We are so grateful that we were with him during the last hours of his life ... We spent hours chatting to him, reminiscing about our childhood and our wonderful mother. We shared laughter and tears together," they told Britain's PA news agency.

"The last year of our father's life was nothing short of remarkable. He was rejuvenated and experienced things he'd only ever dreamed of."

Moore raised nearly 32.8 million pounds ($45 million) for the National Health Service (NHS) during the coronavirus pandemic last year by walking up and down his garden using a walker. He planned to originally raise 1,000 pounds in honor of his 100th birthday.

His efforts were praised by the nation, and he was later knighted by Queen Elizabeth II.

A Twitter account run on behalf of the royal family said the queen would be sending a private message of condolence to Moore's family.

"Her Majesty very much enjoyed meeting Captain Sir Tom and his family at Windsor last year," the tweet added. "Her thoughts and those of the Royal Family are with them."

British Prime Minister Boris Johnson described him as a "hero in the truest sense of the word" due to his military history and by "cheering everyone up" during the health crisis last year.

"He became not just a national inspiration but a beacon of hope for the world," Johnson tweeted in a statement. "Our thoughts are with his daughter Hannah and all his family."

In response to his death, the flag above Johnson's home at 10 Downing Street, in London, will fly at half-mast, a spokesperson for Johnson said.

It is typically only lowered in response to the death of a member of the royal family, a foreign ruler, a former prime minister or minister for the four British home nations or when the queen has commanded it to do so.

Moore was born on April 30, 1920, in West Yorkshire, England. He later enlisted in the army when he was 19 at the beginning of World War II, a biography on the British Army's website states. He served in both India and the Burma campaign during the war and then later became an instructor in armored warfare. After his army career, he moved into the corporate world where he became a managing director of a concrete company.

Moore was admitted to hospital on January 12 where he was diagnosed with pneumonia, his family said. After returning home, he then tested positive for Covid-19 on January 22. His family added that due to the medicine he was on for pneumonia, he was unable to receive a Covid-19 vaccine.