The Duke of Edinburgh has been involved in a road traffic accident close to the Sandringham Estate but was not injured, Buckingham Palace has said.
Police attended the scene but the 97-year-old did not require medical attention.
An eyewitness told the BBC that Prince Philip walked away from the crash.
They added that the Duke appeared “very, very shocked” in the immediate aftermath of the incident, which happened shortly before 3pm (GMT) on Thursday.
A picture shared on social media and sent to a local radio station showed at least two vehicles by the roadside close to the estate.
The picture shows police in attendance and a Land Rover vehicle – which the duke was reportedly driving – on its side.
Another car is seen further away from the road.
Two other people involved are believed to have suffered minor injuries.
Prince Philip has spent an increasing amount of time at Sandringham, a sprawling estate in Norfolk, following the announcement of his retirement from public life in 2017.
He is currently there alongside the queen, who normally stays at the country retreat until mid-February.
The incident comes after a period of relative ill-health for the previously healthy duke.
Philip has always been known for his active lifestyle but has, in recent years, suffered a number of health problems.
In May 2018, it was reported that the duke suffered a fractured rib just days before the Royal wedding of his grandson Prince Harry to Meghan, Duchess of Sussex.
The Sun newspaper reported that Philip suffered the injury while in the bath.
That incident came just six weeks after Philip underwent a general anaesthetic for a full hip replacement at King Edward VII’s Hospital in London
He left hospital to recover at Windsor Castle nine days later.
At the time, orthopaedic surgeons spoke of the risk attached to such an operation for the then 96-year-old – but they added that the Duke’s general fitness would be more important than his age.
Sandringham: The Royals’ favourite country retreat
Sandringham House is one of two personal and private residences owned by The Royal Family, unlike the Royal palaces such as Buckingham Palace that belong to the Crown.
Located in the Norfolk Coast Area of Outstanding Natural Beauty, the house stands in a 20,000-acre estate and is Grade II listed along with its landscaped gardens, park, and woodlands.
The house first came under Royal ownership in 1862 and was a country residence for the Prince of Wales, the future King Edward VII who passed it down to his son, King George V.
The Queen inherited Sandringham from her father in 1952 with the Duke of Edinburgh taking overall responsibility for its management.
Sandringham is one of the Royal Family’s favourite homes and it is where the Queen usually celebrates Christmas, where she is joined by many members of The Royal Family.
Traditionally they visit the Church of St. Mary Magdalene on the Sandringham Estate on Christmas morning.
The Queen’s father, George VI, died at Sandringham in February 1952.