The Princess Royal is in hospital after sustaining a head injury from a horse at her Gloucestershire estate yesterday.

Buckingham Palace described Princess Anne’s condition as stable, but she is not expected to be discharged until later this week.

The 73-year-old royal has been busy standing in for her brother King Charles during his cancer battle, but now she will be forced to cancel forthcoming engagements including a trip to Canada later this week on the advice of her medical team.

The princess was walking in the grounds of Gatcombe Park, where she and her grandchildren regularly ride, when she was injured by a horse, which caused ‘“minor” wounds to her head and a concussion, according to the Palace.

Anne’s husband Sir Tim Laurence and her children Peter and Zara were at the family home at the time of the accident.

An air ambulance was called to the scene and treated the princess, who was later taken to Southmead Hospital in Bristol (accompanied by her husband, but not by air ambulance), where she is now under observation. The palace said the princess is expected to stay at Southmead Hospital until she is able to go home.

The Princess was expected to be at tomorrow’s Japan State Visit, but has had to postpone all forthcoming engagements. “Her Royal Highness sends her apologies to any who may be inconvenienced or disappointed as a result,” a palace spokesperson said.

The aide added that the princess was “recovering well” and in a “comfortable condition.”

The Princess’s last public appearance was at Royal Ascot, riding in the carriage procession alongside Lady Gabriella Windsor. A keen equestrian and former Olympian, her love of horses is well known. At the King’s recent birthday parade, Princess Anne rode on horseback in her role as Gold Stick.

Palace aides have not released details of how the Princess sustained the injury but have said the royal, who is famous for her no-fuss attitude, is expected to make a full and swift recovery.