Children's Secretary Ed Balls was issued with a £60 fine for driving while using a mobile phone, it was disclosed.
Mr Balls, who is married to fellow Cabinet minister Yvette Cooper, said that the incident happened last Sunday when they were driving from Yorkshire to London with their children.
"Although our car has hands-free, I took my phone off the cradle because I did not want to wake the kids," he told The Sun.
"We got waved down by a police car almost immediately. I had no points on my licence and accepted the fine and three points without complaint.
"I 100% support the law on mobile phones - it's there to protect the safety of all drivers, passengers and pedestrians."