Prince Michael of Kent helped police arrest a driver suspected of using his mobile phone while driving last week
The Prince was travelling in an unmarked police car during a visit to the Thames Valley force on April 1, and was there to see what officers have to deal with on the county's roads.
While on the M4 near Three Mile Cross in Berkshire, the Prince spotted a motorist who appeared at first to be asleep at the wheel. As they pulled alongside, they could see that he was looking down and seemed to be using his phone to send a text message.
Sergeant Phil Hanham, who was driving the Prince, said: 'Between the two of us, we were able to call in a second vehicle and that man has now been dealt with.'
He also said that the Prince had told him he often uses this stretch of road, and had regularly seen people committing offences such as undertaking.
'He was very keen to work alongside us and spot a few dangerous things as well,' said Sergeant Hanham.