There was nothing to be achieved from prosecuting the Duke of Edinburgh over his car crash, a royal commentator has said.

Hugo Vickers insisted there was no chance that Prince Philip would have been fined or endured more serious sanctions for the accident involving a mother and a baby.

The Crown Prosecution has announced that the 97-year-old Duke, who voluntarily surrendered his driving licence, would face no further action over the collision on the A149 at Babingley, near King's Lynn.

Royal biographer Vickers told the Press Association: 'If the police think he's a dangerous driver, what is the outcome they want?

'They want to get him off the road. He's off the road - fine, finished.

'That would happen to anyone. I think if I was 97 and I voluntarily surrendered my licence, they would say 'Well, thank you very much - that's it, that's all we ask you to do'.

'What else are they going to do? Are you going to fine him? Are you going to put him in prison? It's ridiculous. The outcome is satisfactory.'

The Duke has apologised for his part in the crash on January 17.

His Land Rover Freelander collided with a Kia carrying a baby, leaving two women needing hospital treatment, after he was dazzled by the low sun as he pulled out a driveway on the Sandringham estate.

Prince Philip's vehicle flipped over and he was trapped before being rescued by a passing motorist.

The nine-month-old baby boy in the other car was unhurt, but both women were treated in hospital, and passenger Emma Fairweather, who broke her wrist, called for the Duke to be prosecuted if found to be at fault.

Vickers said he was a very sensible and practical man, who had done the correct thing by giving up his licence.

'He is a practical man and he will have been very shocked by what happened, I'm sure, because it could have been very, very serious,' the writer said.

He added: 'There's nothing possible to be achieved from prosecuting him or sending him on a dangerous driving course.'

While Prince Philip can no longer drive on public highways, he is allowed behind the wheel on private roads.

'He can still drive around the estates at Sandringham and Windsor,' Vickers said.