An overenthusiastic hound dog caught the wrong scent and ended up on the M23.
Trail hound Jack caused traffic chaos after escaping from his owners and running more than a mile onto the M23 but fortunately lived to tell the tale.
Sussex Police were called after Jack was seen running on the M23 at junction nine northbound at Gatwick at 2.50pm on Tuesday.
The road was blocked and the dog was caught 20 minutes later by a driver who managed to grab his lead with the road re-opening at 3.24pm.
Jack had broken away from his owners during a walk in Haroldsea Drive in Horley. It was a male trail hound called Jack and had broken free while being taken for a walk by youngsters.
He was then transferred from PC Vicky Lank's patrol car to an air-conditioned dog unit from Gatwick to protect him from the extreme afternoon heat and driven back to its owners.
PC Lank said: "The road was temporarily closed because it is clearly dangerous if drivers are swerving to avoid a dog running loose.
“Thanks are due to motorists whose journeys were delayed, but it's pleasing that no one was hurt and that Jack was returned safe and sound to his owners."