THERE is a journalistic aphorism which states that "dog bites man" is not newsworthy, but "man bites dog" most certainly is.

Similarly, the headline "Traffic chaos on M74 barely raises an eyebrow, but put up the legend "Dog causes traffic chaos taking control of tractor on the M74" and one would think the world had gone barking mad.

Such was the case yesterday. At 8.34am Traffic Scotland tweeted "RTC to due to dog taking control of tractor... nope, not joking. Farmer & police at scene, vehicle in central res.", adding the hashtag #maycausetailbacks. Within two minutes that had been trumped on Twitter, when film director Michael Hines amended the tag to #maycausetailwags. On, reader John Paterson quickly posted: "Was it a doberman pincher?"

It transpired that the culprit was in fact a collie, named Don, which had jumped on to a mini tractor while the farmer was tending to a lamb in a field next to the motorway and leaned on the controls. The vehicle, with the collie onboard, then careered across the motorway before striking the central reservation.

Social media was awash with canine puns, ranging from "Ruff morning then" to "Police investigating, no leads", brightening the morning of many - except, one would guess, those stuck in the ensuing traffic jam. For them, the feeling would have been of - apologies - melancholy.