"Let's hope you don't enjoy it," quips Steve, the ghillie, as he stands fixing the end of my fishing rod, "or you'll want to spend the rest of your life doing it. I know people who'd fish in a dirty puddle."

I'm in Norham, on the river Tweed, and about to try fly-fishing. Steve has taken one look at me and decided it's probably not the best idea to put me in waders and send me out to the middle of the river: "No good can come of that."

Instead, he's taking me out in a special rowing boat that has what looks like a bar stool at one end.

"You sit there," he tells me. I look around for the cocktail cabinet. There isn't one. But I do get a lick on the lips from Steve's spaniel, Ruger.

I'm going to try to catch a salmon but it's going to be a tall order.

"This time of year," he tells me as he rows, "they want to be away. But there's lots still stuck here. They need a flood. They like the bedrock to lie in. But this time of year they yearn for the pebbles and the shingle. They're desperate to spawn."

"Aren't we all?" I reply, staring out over the river.

The location is idyllic. We're heading out in the late afternoon, and the sun, threatening to drop like a stone, has burst dramatically from the low cloud. Other than the sound of Steve's oars through the water, nothing can be heard.

"There's a family of otters live up the bank," he tells me. "You never used to see them. Now they're always out. Even during the day. Last year, I sat here for an hour watching a mother and two kits on that sandbank. She caught a flounder, brought it up for them. And the two of them sat staring at it while the flounder's tail kept slapping them in the face."

Steve's story reminds of the time I went to Skye. I was on a walk, and on the way back I bumped into a toothless woman who asked me if I wanted to give her a fiver and "have a go in her otter hide". I paid up and was shown into a shed that stank of urine. On one wall was a terribly faded painting, clearly supposed to be of an otter but looking more like a dachshund. I sat there for three hours, saw nothing and went back to my hotel.

"She's not still doing that is she?" said the hotel manager, after asking what I'd been doing all day. "There haven't been otters here for 20 years."

But back to the fly-fishing. I've cast my line and I'm following it as it drifts north to south, and then casting it again. Nothing's biting. To fill the gap, Steve tells me about his first time out as a ghillie: "There was a chap in the middle of the river. And I'd told him not to go in further than his waist. And I was up the bank, ahead of him. And I turned round and suddenly I see him, arms in the air, and in trouble. And I ran back to where he was and he'd disappeared. So I dived in. And I couldn't find him. And then I saw his white jumper and he was down in the weeds. And I dived down, grabbed him and pulled him up. But I had to breathe. So I had to let go, come up, then dive again. And I dragged him to the bank. And he wasn't breathing."

I'm sitting, mouth agape, eyes wide. "Were you terrified?"

"I was absolutely shitting myself," he replies. "But then another fisherman ran over. And he was a doctor. And he sent me off to get an ambulance. And he brought him back."

At that moment, a massive salmon leaps from the water to the left of my line. Then another leaps to the right. My line goes a bit tight.

"Oooh," I say, and turn to grin at Steve. "Shall I reel it in?" I ask, enthusiastically. I do. I've caught a weed, which, as Steve rightly points out, is "better than nothing".

• Crabtree & Crabtree (01573 226711, crabtreeandcrabtree.com) provided instruction with Steve Herdman (from £50 a day in peak season) and accommodation at The Boathouse (crabtreeandcrabtree.com/The_Boathouse-propertyid:11647), which sleeps 10 from £1,300 a week