The Queen and Boris Johnson have led tributes to Captain Sir Tom Moore who has died aged 100 after testing positive for COVID-19.
The centenarian, who captured the hearts of the nation during the first lockdown, was being treated in Bedford Hospital for help with his breathing after he developed pneumonia in recent weeks.
Last year, he raised more than £32m for the NHS after walking 100 laps of his garden - and his family hailed the last year of his life as "nothing short of remarkable", adding: "He was rejuvenated and experienced things he'd only ever dreamed of".
Buckingham Palace said the Queen and the Royal Family's thoughts are with his loved ones and she is sending a private message of condolence.
Her Majesty knighted him at Windsor Castle last July in recognition of his fundraising efforts.
The flag above 10 Downing Street is flying at half-mast and the prime minister has spoken to Sir Tom's daughter Hannah Ingram-Moore to offer his condolences.
Boris Johnson said: "Captain Sir Tom 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 this country's deepest post-war crisis he united us all, he cheered us all up, and he embodied the triumph of the human spirit.
"It is quite astonishing that at the age of 100 he raised more than £32m for the NHS, and so gave countless others their own chance to thank the extraordinary men and women who have protected us through the pandemic.
"He became not just a national inspiration but a beacon of hope for the world. Our thoughts are with his daughter Hannah and all his family."
Health Secretary Matt Hancock tweeted: "I'm so sorry to hear that Captain Tom has passed away in hospital.
"He was a great British hero that showed the best of our country & I send my best wishes to his family at this time."
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."
Singer Michael Ball, who recorded a charity single with Sir Tom that reached number one, wrote on Twitter: "Rest in peace @captaintommoore. A wonderful life so well lived and a hero and fighter to the very end.
"So very very sad. Love and prayers for @Hannah_I_M and all the family."
Ruth May, chief nursing officer for England, said Captain Sir Tom gave the country a "boost when we most needed it".
She said: "On behalf of everyone in the NHS, I want to pay tribute to Captain Sir Tom Moore who has been the model of all that has been good about our country's response to COVID-19.
"People rightly marvel at the tens of millions of pounds Captain Sir Tom raised for the NHS.
"But for me his biggest achievement and most important contribution to helping my fellow nurses, doctors and all those in the NHS responding to coronavirus, has been how he brought the country together and gave us all a boost when we most needed it."