Captain Sir Tom Moore has died with coronavirus.
The 100-year-old, who raised almost £33m for the NHS, was taken to Bedford Hospital after requiring help with his breathing on Sunday.
His daughter Hannah Ingram-Moore said he had been treated for pneumonia over the past few weeks and last week tested positive for Covid-19.
Buckingham Palace said the Queen is sending a private message of condolence to the family of Capt Sir Tom.
The Royal Family tweeted: “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 Army veteran won the nation’s hearts by walking 100 laps of his garden before his 100th birthday.
In a statement, Capt Sir Tom’s daughters Mrs Ingram-Moore and Lucy Teixeira said: “It is with great sadness that we announce the death of our dear father, Captain Sir Tom Moore.
“We are so grateful that we were with him during the last hours of his life; Hannah, Benjie and Georgia by his bedside and Lucy on FaceTime.
“We spent hours chatting to him, reminiscing about our childhood and our wonderful mother. We shared laughter and tears together.
“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.
“Whilst he’d been in so many hearts for just a short time, he was an incredible father and grandfather, and he will stay alive in our hearts forever.”
Capt Sir Tom’s daughters said the care he received from the NHS was “extraordinary”.
They said staff had been “unfalteringly professional, kind and compassionate and have given us many more years with him than we ever would have imagined”.
The Army veteran, originally from Keighley in West Yorkshire, came to prominence by walking 100 laps of his garden in Marston Moretaine, Bedfordshire, before his 100th birthday during the first national lockdown.
Capt Sir Tom joined the Army at the beginning of World War Two, serving in India and Myanmar, then known as Burma.
Labour leader Sir Keir Starmer tweeted: “This is incredibly sad news. Captain Tom Moore put others first at a time of national crisis and was a beacon of hope for millions. Britain has lost a hero.”