“Her royal highness is recovering well, is in a comfortable condition and is being kept in hospital as a precautionary measure for further observation,” a Buckingham Palace spokesman said.

The 73-year-old, the only daughter of the late Queen Elizabeth, had been walking in the grounds of Gatscombe Park estate where her home is located when she suffered minor injuries to her head, a royal source said.

The source added that there were horses in the vicinity and her medical team said the head injuries were consistent with impact from a horse’s head or legs.

“The king has been kept closely informed and joins the whole Royal Family in sending his fondest love and well-wishes to the princess for a speedy recovery,” the Buckingham Palace statement said.