The Duke of Edinburgh will not face prosecution over his road crash near the Sandringham estate, the Crown Prosecution Service has said.
The 97-year-old voluntarily gave up his driving licence on Saturday after his Land Rover Freelander collided with another vehicle in Norfolk last month.
He later apologised to the occupants of the other car - two women and a baby.
The CPS says it decided that it would not be in the public interest to prosecute the duke.
Chris Long, Chief Crown Prosecutor from CPS East of England, said: "We took into account all of the circumstances in this case, including the level of culpability, the age of the driver and the surrender of the driving licence."
The duke escaped injury after his vehicle landed on its side following the collision with a Kia on 17 January on the A149 near the Queen's country estate.
Two days later Norfolk Police gave him "suitable words of advice" after he was pictured driving without a seat belt.
He wrote to one of the passengers in the Kia - Emma Fairweather, who broke her wrist in the accident.
In the letter, dated 21 January and reproduced by the Sunday Mirror, the duke acknowledged the "very distressing experience".
"I would like you to know how very sorry I am for my part in the accident," he wrote, on Sandringham House headed paper.
"The sun was shining low over the main road. In normal conditions I would have no difficulty in seeing traffic coming... but I can only imagine that I failed to see the car coming, and I am very contrite about the consequences."
Ms Fairweather had previously criticised the duke for a lack of communication following the crash.
Witnesses described how they saw the Land Rover roll and end up on the other side of the road. One man, who helped free the duke from his car, said he saw the vehicle "careering" across the road.
The duke, who is four months short of his 98th birthday, famously drove the Obamas when the then-US president and First Lady visited Windsor in 2016.