The Queen has cancelled a traditional Christmas shoot and stud trip as Prince Philip remains in hospital, according to reports.
Her Majesty normally visits the Royal stud on the first day of her Christmas break after leaving London for the Sandringham Estate in Norfolk on Friday.
She usually sees her horses and meets with staff and despite preparations for her usual visit, the monarch did not arrive.
The usual pheasant shoot on Saturday also did not take place, the Mail Online reports.
Philip remains at the King Edward VII's Hospital in central London for treatment relating to a "pre-existing condition".
The Queen now faces a wait to see if the Duke of Edinburgh will be able to join her for Christmas.
The duke's planned admission on Friday to the private central London hospital, which has been treating members of the royal family for decades, was described as a "precautionary measure" by Buckingham Palace.
The Queen did not change her schedule and left Buckingham Palace for Norfolk by train, to begin her traditional festive break at her private Sandringham estate, where the duke spends much of his time since retiring from public duties.
As a regular church-goer Queen is expected to attend Sunday service, but it remains doubtful that her husband will join her.
The duke, who turned 98 in June, has generally enjoyed good health, appearing to recover well from a planned hip replacement operation in April 2018.
According to reports, his admission follows a spell of ill-health - with some reports claiming the duke had a fall recently, and others saying he had been battling a flu-like condition.
Uniformed police officers stood guard outside the hospital entrance on Saturday morning alongside a doorman wearing a top hat while camera crews were set up across the road.
Philip escaped with minor injuries after a dramatic car crash near Sandringham in January, but in the past decade has been admitted to hospital for abdominal surgery, bladder infections and a blocked coronary artery.
A Buckingham Palace statement on Friday said: "The Duke of Edinburgh travelled from Norfolk this morning to the King Edward VII Hospital in London for observation and treatment in relation to a pre-existing condition.
"The admission is a precautionary measure, on the advice of His Royal Highness's doctor."
The duke was not taken by ambulance and was expected to be in hospital for a few days.
Philip is known for his "no fuss" approach and is unlikely to receive many visitors while he is being treated at the hospital.
A source told the Mail: "He doesn’t want the family coming to see him when he is in hospital.
"He wants to be in and out with minimal disruption to any festive plans and he certainly doesn’t want the family to spend time at Christmas traipsing to his sick bed."
Buckingham Palace would not go into details about Philip's pre-existing condition, or the nature of his treatment, but there is likely to be concern for the duke among well-wishers given his age.
His decision to retire from public duties during 2017 was not health-related, Buckingham Palace said at the time of the announcement.
The duke is an advocate of healthy eating combined with exercise. He once said he more or less followed the Atkins diet and he drinks only moderately.
He has given up riding carriages competitively, but earlier this year was photographed in the grounds of Windsor Castle holding the reins as he guided a horse and carriage through the estate.