Roy Warne, 75, described how the crash unfolded in front of him and saw the duke’s car “tumbling across the A149.”
He revealed how he helped to pull Prince Philip, 97, from his seat.
Speaking to ITN, Mr Warne said: “Well he was trapped in the car and I told him how to move to free his legs to help get him out.”
After helping the royal out of the car, he said he heard Philip say he had been “dazzled by the sun”. He also asked if everyone else in the other vehicle was alright.
While the duke was uninjured, he was left “shocked and shaken” by the accident.
Mr Warne said that when he first went to the scene, he went to the other car first: “There was smoke and I thought it might explode, and got the baby out.”
Norfolk Police have said that investigations will continue today into the collision between the Duke’s Land Rover and a Kia at the junction of the B1439, where it meets the A149.
They confirmed the driver of the Kia, a 28-year-old woman, suffered cuts to her knee while the passenger, a 45-year-old woman, sustained a broken wrist. Both casualties were treated at the Queen Elizabeth Hospital in King’s Lynn and were discharged last night.
Police can also confirm a nine-month-old baby boy was in the Kia at the time of the incident and was uninjured.
Norfolk Police said officers were called to the A149 at Sandringham just before 3pm on Thursday after the collision.
The force confirmed both drivers were breathalysed and the tests proved negative.
It said: “It is force policy to breath test drivers involved in collisions. We can confirm both drivers were breath tested and provided negative readings.”