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 Philip would have been fined or endured more serious sanctions for the accident involving a mother and a baby.

The Crown Prosecution announced on Thursday that the 97-year-old duke, who voluntarily surrendered his driving licence, would face no further action over the collision on the A149 near Sandringham, Norfolk.

The Duke of Edinburgh at the Braemar Royal Highland Gathering in 2017 (Andrew Milligan/PA)

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.”

Royal writer Hugo Vickers (right) with the Queen and the Duke of Edinburgh at the unveiling the Jubilee Walkway panoramic panel in 2007 (Shaun Curry/PA)

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.

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

Glass and car parts on the side of the A149 near to the Sandringham Estate where the Duke of Edinburgh was involved in a road accident (John Stillwell/PA)

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 Philip to be prosecuted if found to be at fault.

Vickers described the duke as 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.”

The Queen and Philip at Balmoral Castle (David Cheskin/PA)

While 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.

“He was never driving in London anyway. He was only driving locally at Balmoral and things … but, unlike many of us, he has got people who can drive him round if need be, such as his police protection officer.

“At that age it must be disappointing because it’s another step towards the curbing of your independence which nobody likes – least of all him.”