‘I was still picking myself up as the Gator crashed through a fence. The last thing I saw before it disappeared was my border collie’s face, gazing benignly back at me’

I’ve been farming sheep and cattle on this hillside in South Lanarkshire, Scotland, for 54 years. I use a John Deere Gator to get about – a utility vehicle bigger than a quad bike but smaller than a tractor. It’s just a little truck with a roll cage, really – it does about 40mph. My black and white border collie, Don, always sits beside me in the passenger seat. I’ve had him about five years now, since he was a pup. He’s not the best dog I’ve had, but he’s good enough.

It was a little after 8am when I spotted the lost lamb. I was in the top field, near where the motorway cuts through my land. The lamb had become separated from its mother. You have to keep them paired up, so I hopped out of the Gator to tend to it while Don stayed in his seat and watched me through the back window. That’s the way we always work – I leave the door open and if I need any help from Don, I shout and out he comes.

Lamb and mother reunited, I turned back to the Gator only to see it lurch suddenly away from me. This was so unexpected it took me a moment to process what was happening. I’d put the handbrake on when I jumped out, as I always do, and I knew Don wasn’t able to release it – had it not engaged properly? I still don’t know how, but it was clear that Don had somehow set the vehicle in motion. He was watching me, without any obvious concern, as the Gator careered away.

My stomach lurched as I saw where it was heading. I didn’t even have time to call out, and anyway, what could I have said? My heart seemed to freeze in my chest as I gave chase, praying I’d be able to throw myself through the open door before disaster struck.

There were no more than 150 yards to the motorway, and the gap was closing fast. I’m pretty fit for a 77-year-old, but even before I tripped I knew I stood no chance of catching up. I fell heavily, winding myself, and was still picking myself up as the Gator crashed through a wooden fence and plunged out of view. The last thing I saw before it disappeared was Don’s face, gazing benignly back at me.

Beyond the fence was a steep, 30ft bank, and at the bottom of that the northbound carriageway of the M74, teeming with rush-hour commuters. I could hear the roar of the traffic. I listened for the sound of an impact or of screeching brakes as I dashed towards the fence, but none came.

Heart in mouth, I reached the fence and peered over. Below me, a man in a high-visibility jacket was standing in the road, holding his arms wide to stop oncoming vehicles. He had broken off from a group of road maintenance workers on the hard shoulder. The Gator was resting against the crash barrier in the central reservation, having miraculously crossed three busy lanes. I couldn’t see Don, but as I approached the Gator he leapt out on to the road, apparently unhurt, and dashed back up the bank and out of sight.

The Gator’s engine was still running as I hauled myself into the driver’s seat. The windscreen had been smashed. I was dimly aware of the growing tailback of cars and lorries as I backed it round and drove it towards the bank. One of the workmen came running to stop me, but I paid him no attention – I suppose I must have been in shock. I’d expected to see a pile-up, and feared there would be casualties. That outcome was still playing out in my head, even as I drove back through the hole in the fence.

By the time the police arrived, the motorway was running normally again. I couldn’t quite believe my luck – it turned out I’d broken a rib when I fell and Don had a slight limp for a couple of days, but the outcome could have been awful. Don was given a special meal that night – I didn’t want him thinking I was angry with him.

As soon as the Gator’s windscreen was fixed, I started using it again, and he jumped in with me as happily as he always has. I’m extra vigilant now; no matter how calm my dog proved in that near-disastrous situation, I don’t think my heart could take another.

• As told to Chris Broughton.

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