David Kennard is, it turns out, famous. He's the human star of Mist: Sheepdog Tales, a children's TV series that airs in more than 20 countries. But he's no actor; he's a farmer through and through.

"I only appear in it when I absolutely have to," he says, softly. "It's the dogs who are the real stars."

He's not lying. His sheepdogs are amazing, and I'm at Borough Farm near Woolacombe with him and Fly, one of the stars of the show. She's a young collie, bright-eyed, lean and eager. She takes one look at my dog, Poppy, laziest beagle in the universe, and ignores her. It's a bit like an Olympian being forced to hang out with Jabba the Hutt.

"How is she with sheep?" David asks as I heave Poppy into his Land Rover. I have no way of knowing. "She barks at pigeons," I offer. "And she chased a squirrel once."

"Hmm," says Dave.

David's Land Rover is a treasure trove of organised mess. It's lovely, old and battered and it's still got a cassette player.

"I've had this in every working vehicle I've ever had for nearly 30 years," David tells me, proudly, holding up a weathered-looking tape of the Pretenders album Learning to Crawl. "I know all the words on it now. Can't sing, mind."

He starts to sing Show Me but gives up after the first line. "We'll head up to the cliffs now, I think," he adds, after a small cough. "Show you how I work the sheep."

At a point just past Mortehoe we put Poppy on a lead, (David loses sheep annually to holidaymakers' dogs chasing them over cliffs) and strike off into a low-hanging mist.

"Can't even see the lighthouse," says David, gesturing westwards. "We used to be wreckers round here. Villagers would stand with lanterns and lure ships onto the rocks and then club to death anyone who made it to shore. So when they built the lighthouse, in 1872, everyone round here was livid. Meant the end of their livelihood. Ah, here it comes. Mist's rising."

As the fog lifts, the lighthouse and a flock of sheep come into view, hugging the clifftop. We're standing above them on a peak and Fly is alert, tail tucked, crouched and waiting. Poppy is behind me, rolling in something unspeakable.

David gives a tiny, soft whistle and Fly is away, edging to the right, following his every command. She negotiates brambles, comes round the flock's flank and then, as David's whistles pierce the air, she drives the sheep away from the cliff and up a narrow path in the gully below us.

"Do you think Poppy could do that?" I ask, nodding down towards my beagle, who is yawning.

"No," says David.

It takes at least two-and-a-half years to train a sheepdog, and to get them to the next level, working a brace (two dogs at the same time with different tonal whistles), takes further years of constant practice.

"Fly's been a nightmare to train," David says as she races back to us. "It's been like driving a Formula One car with your wellies on."

There's a fine line between herder and killer. All dogs have the instinct to hunt and chase, but a good sheepdog needs bravery too. "A weak dog will let its tail rise. The rams know this and they'll take advantage. The dog needs to stand her ground."

"Look at that," David adds, pointing to a white orb below us. "Chinese lantern. I'm constantly having to pick those things up. They wreak havoc. If they land in a silage field, the wire gets churned up in the machines into tiny bits, the cows eat it and they have to have an operation. They're a menace. People let them off, think "Ooooh, aren't they lovely!" and don't give a thought to where they land."

It's a real treat spending the afternoon with David. He's glorious company: he takes me off the beaten track to show me the best of the Devon coastline and creeps with me down a steep incline where we can watch seals gather in a pool below us. Not only that, but he regales me with endless local tales.

"They say there's bodies buried over there," he whispers, gesturing to a small plain between two peaks. "Old Ray in the village reckons so. He's the last of the Wreckers."

"Is your favourite film Babe?"

"Yes," nods David, smiling. "I had a friend once tried to train up a pig. It didn't really work out. Nothing's cleverer than a dog."

Poppy's eating some horse manure. I beg to differ.

• Borough Farm (boroughfarm.co.uk) runs the last of its summer displays by the stars of Sheepdog Tales at 6pm next Wednesday. Adults £5, children £2.50. A shepherd's experience with David and his dogs costs £20 for around two hours

Follow Emma Kennedy on Twitter at @EmmaK67