Horses on the M23 near Crawley are causing gridlock.
At around 7.30am, Sussex Roads Police tweeted that 'traffic was at a standstill' due to the equine blockage.
At 8am, they said: "The horses have been contained for the time being and we're trying to keep them calm: we're now trying to locate a suitable vehicle to transport them in. Traffic is still held.
"In the meantime: you can access the northbound #M23 from Junction 10. The horse owner has been found and is en route as quickly as they can, but it will be a little while yet."
At 8.30am, police said that Highways England was 'trying to turn some of the trapped traffic around to get people on their way' and thanked drivers for their patience.
According to traffic reports, six horses were loose on the road.
At 9.45am, they tweeted: "Half of the horses have been loaded into a vehicle, and we're just trying to persuade the rest in. They are, we are told by people with much better knowledge of horses than us, yearlings, who have never been in a vehicle before, so they're frightened & skittish about getting in."
At around 10am, Sussex Roads Police said the horses had been rounded up and the M23 had been reopened.