The Duke of Edinburgh has been admitted to hospital after feeling unwell, Buckingham Palace said. Prince Philip, who is 99, was admitted on the advice of his doctor and a palace statement said it was a precautionary measure. The statement said: “His Royal Highness the Duke of Edinburgh was admitted to the King Edward VII hospital in London, on Tuesday evening. “The duke’s admission is a precautionary measure, on the advice of [his] doctor, after feeling unwell. The duke is expected to remain in hospital for a few days of observation and rest.” Philip, who was said to be in good spirits, went by car to the hospital and it was not an emergency admission. He is said to have walked into the hospital unaided. A source said the illness was not Covid-related and the stay in hospital was purely precautionary. He had been feeling unwell for a short period and the doctor was called to Windsor Castle, where he and the Queen have been shielding. The Queen remains at Windsor. No further details of his condition were being released, Buckingham Palace said. A spokesman for the prime minister, Boris Johnson, said: “The PM sends his best wishes to the Duke of Edinburgh as he undergoes a few days of rest in hospital.” The Queen and Philip, who celebrated their 73rd wedding anniversary in November, received their Covid-19 vaccinations in January. Philip, who will celebrate his 100th birthday on 10 June, spent four days in hospital in December 2019 for what royal officials said was observation and treatment for a pre-existing condition. He was discharged on Christmas Eve and driven to Sandringham to spend Christmas with the Queen. He has suffered a number of ailments over the years, including being treated for a blocked coronary artery at Papworth hospital, in Cambridgeshire, in December 2011, and a bladder infection in June 2012, forcing him to miss the Queen’s diamond jubilee celebrations. Exploratory surgery on his abdomen followed in June 2013 and he began to use hearing aids in 2014. He later pulled out of a Battle of Jutland anniversary event in June 2016 citing a minor ailment, which was followed soon after by his retirement from public duty in 2017. In June 2017, after a day in sweltering conditions at Royal Ascot, he was admitted to hospital as a precautionary measure for treatment for an infection arising from a pre-existing condition. He was discharged after a two-night stay. He also had a hip replacement operation in 2018. In January 2019 he was unhurt after the vehicle he was driving was involved in a traffic accident that injured two people near the Sandringham estate in Norfolk.