The Duke of Edinburgh missed the Royal Family's annual Boxing Day shoot today as he remained in hospital following a heart scare.
Philip, 90, was admitted to Papworth Hospital near Huntingdon in Cambridgeshire on Friday night after complaining of chest pains.
He underwent treatment for a blocked coronary artery and was kept in hospital as a precaution.
The Duke had hoped to be discharged from hospital in time for today's shoot, but was expected to remain in hospital for a fourth night tonight.
Despite the setback, he was said to be in good spirits.
A Buckingham Palace spokesman said: "The Duke of Edinburgh continues to make good progress from the procedure. He remains in hospital under observation and in good spirits."
The Palace said there was no change this morning but added that the Duke had spent another "good night" at Papworth, which is a specialist heart hospital.
Following tests, doctors discovered a blocked artery and he underwent a "minimally invasive procedure of coronary stenting", which was declared a success, but he has been kept in so doctors can keep a close eye on his recovery.
This is the most serious health scare suffered by the Duke, who is known for being robust and active.
Yesterday, the Duke of Cambridge and his younger brother Harry drove separate cars to the hospital from Sandringham, the Queen's private Norfolk estate, taking the Duke of York's daughters Beatrice and Eugenie and the Princess Royal's children Zara and Peter with them for a 45-minute visit to their grandfather.
They made the journey after enjoying lunch at Sandringham, having changed into more casual attire than their earlier outfits for the traditional Christmas church service at the estate.
William, who is rarely photographed wearing glasses, wore them as he drove a Range Rover with Peter and Zara as his passengers, while Harry drove an Audi with Beatrice and Eugenie inside.
Their visit would have been a welcome distraction for the Duke who is thought to have missed his first Christmas morning service at Sandringham, an annual tradition for the Royal Family since the early 1990s.
Around 3,000 well-wishers gathered outside St Mary Magdalene Church to see the royals, including the Prince of Wales and Duchess of Cornwall, the Duke of Cambridge, Prince Harry, the Princess Royal, the Duke of York, and the Earl and Countess of Wessex.
It was the Duchess of Cambridge's first time at the service, which was also attended by England rugby player Mike Tindall and the Queen's granddaughter Zara Phillips, who married in the summer.
The Queen's Christmas Day message, recorded before her husband fell ill, described the importance of family.
In her annual address to the nation, she spoke of the weddings of the Duke and Duchess of Cambridge, and of Zara and Mike Tindall.
In times of hardship we often "find strength from our families" and in a crisis communities "break down barriers and bind together" to help each other, she said.
"The importance of family has, of course, come home to Prince Philip and me personally this year with the marriages of two of our grandchildren, each in their own way a celebration of the God-given love that binds a family together."
The Queen is being briefed on her husband's condition continually and no date for his discharge from hospital has been set.