I'm in Windermere and I'm trying to get into a brightly coloured Land Rover. Across the windscreen is emblazoned a rousing and hearty cry, "Hail! Men of Kankku!" There's a funny story about that. But Nick Fieldhouse, the owner of Kankku off-road driving experiences, has sworn me to secrecy. Suffice to say, it's a tale of defiance and derring-do, but that to one side, I'm still trying to get into the driving seat.

"Sorry," I say, as I have to be shoved upwards. It's a bit like watching Mrs Tiggy-Winkle attempt an assault course. But then we are in Beatrix Potter country. I am nothing, if not appropriate.

Nick is a quiet man. He's Cumbrian born and bred and has lived on the lakes all his life. He used to have a water-ski business but when a 10mph speed restriction was introduced on Windermere in 2005 he had to reassess. He bought a Land Rover, set off to explore the network of public off-road trails that stretch across the Lake District and decided to launch Kankku.

I'll be honest. It's not what I expected. For some reason I imagined bumping along at speed, screaming, with my eyes closed, but trail driving is the exact opposite. Slow and steady is the name of the game. The trails aren't so much tracks, more massive boulders that seem utterly impassable. I'm staring ahead at a sheer incline of jagged rock. "You are joking, we're driving up that?" I ask, incredulous. But Nick is inscrutable, like a martial arts master. "Drop down to first," he says, calmly. "We can get up anything."

I've never driven a car with a low ratio gearbox before and the thing I'm struggling to come to terms with is the fact I don't actually have to drive it at all.

"Take your foot off the clutch," growls Nick. "Clutches are for girls."

I'm now sitting, my feet swinging idly, as the Land Rover drives itself up on to the first ridge of boulders. She's the Lake District equivalent of Herbie, or KITT the Knight Rider. I'm half expecting to hear the car speak to me. Something like, "Haw tha jen, dumbleheed?" or "I can't be arrished lowping ower t'yat today."

We hit the first steep ridge of rocks. All I have to do is keep my hands on the wheel and try to steer a path of least resistance. Finally, I get to put my foot on the gas to give the Land Rover some climbing welly and, as I do, the whole thing tips rather serenely over to one side. I can't help feeling I'm about to roll it and, because I am not made of sturdy stuff, I let out a small yelp.

"Stop worrying," says Nick, "and keep that gas going."

Nick really is wonderful. He might be the calmest man I've ever met, and with his guidance I settle into the driving. It's incredibly relaxing and not only is it an adventure in the truest sense, but as we pass through Grizedale and Ickenthwaite and come out at the top of Coniston Water, it's hard to imagine a more beautiful setting. Moorland, heather and heath are ours for the exploring, and after lunch Nick takes me to Cathedral Cave in Little Langdale. It's breathtaking. He points to a dark hole in the cliff side and tells me to "Go first."

I stare into it. It's a proper abyss. "Just keep your hand on the left hand side," Nick tells me, walking behind me. I keep going. It's so dark I can't see the hand in front of my face. I won't lie. I'm terrified. I tell Nick this and I hear him give a soft tut.

"Do you want to hold me hand?" he asks.

Yes I do. And so he takes over and leads me the full length of an old slate mining tunnel until we finally see an orb of light in the distance. I've never walked through a mountain before. It's exhilarating. "Right," says Nick. "Now all you have to do is get back into the Land Rover."

And this time, I do it in one go.

• The lesson was provided by Kankku (015394 47414, kankku.co.uk), which has driving trips from £149 per vehicle (for up to four people). Accommodation provided by The Waterhead Hotel in Ambleside (08458 504503, englishlakes.co.uk/hotels/waterhead, doubles from £113)