King Charles III's sister Anne released from hospital after horse accident

Princess Anne, the sister of Britain's King Charles III, has been discharged from hospital where she was treated for concussion after being struck by a horse at her country estate.

Anne, 73, suffered concussion and minor head injuries at Gatcombe Park in southwestern England on Sunday evening and was taken to hospital in Bristol. 

It is believed she was struck by a horse as she was walking within the protected perimeter of the sprawling estate, which hosts equestrian events.

The princess's medical team said at the time her injuries were consistent with a potential impact from a horse's head or legs.

The Princess Royal, as she is also known, is a skilled horsewoman who competed at the 1976 Montreal Olympics, and has a reputation as the hardest-working royal.

She has stepped in to represent Charles while he postponed public engagements during his cancer treatment, and rode at his official birthday parade earlier this month.

But the accident forced her to withdraw from an appearance at a state banquet on Tuesday evening for visiting Japanese Emperor Naruhito, and cancel an upcoming trip to Canada.

Her husband Tim Laurence was seen earlier in the week leaving Southmead Hospital in Bristol after visiting his wife.

He thanked the medical team at Southmead Hospital "for their care, expertise and kindness during my wife's short stay."

Buckingham Palace said on Monday that Anne was in hospital "as a precautionary measure for observation and was expected to make a full and swift recovery." (AFP)