A family driving home after buying a new car had to pull over after finding a 5ft-long snake inside. A couple were alerted by their child that a snake had wrapped itself around one of their dog's legs.
Central Motorway Police Group said one of its patrols came across the family on the hard shoulder of the M5 in Worcestershire, between junctions seven and eight, at about 9:00pm on Thursday.
"When we found them they were a bit shaky," Sgt Dave Lonsdale said.
He said they were on the way home after buying the car in Sheffield. They did not know how the snake got there.
A reptile company was called and, using pictures taken by officers, identified the reptile as a harmless corn snake.
But it crawled into the structure of the car and they were unable to find it.
In the end the couple decided to continue their journey with the intention of looking for the snake properly when they got home.
Sgt Lonsdale added: "The officers assessed the scale of the problem but ultimately the couple knew the snake would not harm them.
It's definitely not a regular occurrence for us."
The force said it was the "most bizarre job for a long time".