The Duke of Edinburgh has been admitted to hospital for treatment relating to a pre-existing condition, Buckingham Palace says.
Prince Philip, 98, left Sandringham, where he has spent much of his time since retiring, to attend the King Edward VII Hospital in London on Friday morning. He was not taken by ambulance and it was a planned admission.
The announcement came as the Queen arrived at the Norfolk estate after travelling from the capital on Friday.
A Buckingham Palace statement said the admission was a precautionary measure advised by the duke's doctor. Philip is expected to be in hospital for a few days.
Queen Elizabeth II and Prince Philip, Duke of Edinburgh. Source: Getty
The announcement was made just before 2pm local time on Friday, shortly after the Queen arrived at the Sandringham.
The 93-year-old monarch, carrying a black handbag and wearing a salmon pink coat and patterned headscarf, was beginning the first day of her Christmas retreat after carrying out her duties at the state opening of parliament on Thursday.
Other members of the royal family will join the couple for part of the festive period.
Events will include the family's traditional Christmas Day church service at St Mary Magdalene Church.
As Philip has continued late into his 90s, concerns for his well-being have increased following a number of health scares.
Abdominal surgery, bladder infections and a blocked coronary artery have seen him admitted to hospital on a number of occasions.
Philip suffers from arthritis in his right wrist, and broke a bone in his ankle playing polo. He also developed synovitis, a rheumatic condition of the tendon in the hand, after a polo fall.
Prince Philip's health scares:
* Late 2011 - rushed to hospital by helicopter from Sandringham after suffering chest pains as the royal family were preparing for Christmas. Treated for a blocked coronary artery and had a stent put it; spent Christmas Day and Boxing Day in hospital
* June 2012 - fell ill with a bladder infection; missed most of Queen's Diamond Jubilee celebrations
* June 2017 - admitted for treatment for an infection arising from a pre-existing condition; discharged after a two-night stay
* April 2018 - planned hip replacement; left hospital after 10 days
* January 2019 - involved in a car crash when the Land Rover Freelander he was driving flipped over after colliding with another car.
