An off-duty police community support officer (PCSO) who stopped to help two young children beside a motorway found their drunken grandfather in a bush.
Aaron Sparrow-Woods spotted a child on the hard shoulder of the A1(M) near Newton Aycliffe, County Durham, on his way home from Ferryhill police station.
He pulled over and found the man face down in undergrowth and another child in the back of the car.
Mr Sparrow-Woods stayed with the children until on-duty police arrived.
The children, aged three and five, were unharmed and later collected by their father.
The 65-year-old grandfather, who was unable to stand, was arrested on suspicion of drinking and driving and child neglect.
He was found to be nearly three times over the legal limit.
Appearing at Newton Aycliffe Magistrates' Court, he pleaded guilty to the offences and was banned from driving for two years and fined £1,000, Durham Police said.
Mr Sparrow-Woods, who has now been nominated for a commander's commendation, said: "Sometimes you just have to follow your gut instinct and thankfully no-one was injured - it could have been a far worse outcome.
"My on-duty colleagues and paramedics were quickly on the scene and I'm glad the children could be safeguarded."
Insp Mike Sammut, of Durham Police, said: "His actions were exemplary at the scene and his dedication afterwards show the very best of our officers who always go above and beyond to help protect the public."