Anyone who has travelled on a rush-hour motorway will be no stranger to a traffic jam.
But motorists on the M74 may be surprised to learn the cause of their latest tailback: a runaway tractor driven by a sheepdog.
Don the collie dog inadvertently caused chaos after leaping into the tractor while his farmer owner was looking the other way.
As Tom Hamilton, 77, tended to a lamb in a field next to the motorway, the over-keen collie leaned on the controls of the tractor and coaxed it into action.
The vehicle, left standing without its brake on, is said to have shot out of the field, crashing through the fence and ploughing across one carriageway.
The sheepdog’s adventures eventually came to a halt when the tractor crashed into the central reservation and was forced to stop in its tracks.
Miraculously, drivers managed to avoid the runaway vehicle and Don survived his perilous journey.
Police, who had been called to the scene by worried motorists, were relieved to find the four-and-a-half year-old dog safe and well.
They cleared the motorway, near Abington in South Lanarkshire, within half an hour, with Don reunited with his owner at his nearby farm.
Mr Hamilton, who has run the sheep farm for 52 years, said: "I was out in the mini tractor and had stepped out of it to get a lamb which looked like it was about to get out of the gate.
"I had not put the brake on the tractor and when I turned round I got a fright as the vehicle was careering down the hill, through a gate and onto the M74."
He added: "Don was fine and did not bark during the incident."
The public were alerted to the unusual scene by Traffic Scotland, who tweeted to say there was a road traffic incidence “due to dog taking control of tractor”.
“Nope, not joking,” it added. “Farmer and police at scene, vehicle in central res. #maycausetailbacks".
They later declared it “the weirdest thing we have ever reported”.
A Traffic Scotland spokesman said: "The dog accidentally leaned on the controls and the vehicle made its way out of the field and onto the M74."
Dog drives tractor, causes traffic disruption.