On a sun-drenched outcrop overlooking a rocky shore on the Isle of Skye, I recently spent two wonderful hours watching an otter work her way in with the tide. Across the Sound of Sleat, a thunderstorm was breaking in the highlands of Scotland. A door-sized sea eagle turned in huge, slow circles down the coast. But here all was peaceful, with the gently lapping waves creeping inwards, bringing the otter closer and closer.

Otters are one of our great conservation success stories. For centuries they were violently persecuted for daring to compete with fishermen. They were crushed in gin traps and otter hounds were specially bred to hunt them.

Things got worse when industry poisoned the rivers. Fish died and toxic mercury built up in the fat of otters and killed them in winter when they drew on that fat in cold weather. Where I grew up, just outside London, otters finally disappeared in the 1970s.

Now thanks to tough pollution laws and otter reintroductions, these wonderful animals are back. Although mostly nocturnal, they’ve been seen from Newcastle to Twickenham and are almost certainly established on the upper reaches of the Thames. They’re in many other towns, too. Slap bang in the middle of Winchester, for example, they are videoed almost nightly at the National Trust’s Winchester City Mill. There's every chance of seeing one if you're enjoying an evening meal in a pub by the river.

Scotland remains the best place to enjoy otters and it’s very easy to see them. Your best chances are to be had where there’s a sheltered, rocky shore, particularly on the west coast. Avoid June to August, because you’ll get eaten alive by midges. I once waited for nearly an hour in a cloud of these nasty little biters before losing my temper and leaping up with my arms waving, just as an otter came round the corner. It promptly vanished.

I try to time my visit for a rising tide early in the morning, when fish are compelled to move with the water. On the last occasion, I had carefully scanned the quiet shoreline from the woods and there was nothing to be seen. However, an otter was there, probably sitting up on some rocks and seaweed, tucking into a fish.

I clambered onto a promontory to soak up the sunshine. Rockpools, limpets and heaps of seaweed stretched out for two hundred feet, where the tide was just starting to creep inwards. And suddenly, in deeper water, I saw a fish floating on its side coming towards me. The otter that held it was hidden, until it reached a rock and climbed out with its prize.

I couldn’t be sure, but it was May and the small size of this otter suggested a female. She tore into the fish with her face scrunched up and chewed it with her mouth open and bits falling out all over the place. Otters always look as though they don’t like the taste of raw fish, but the face-pulling is probably more to do with spitting out the scales, spines and bones that don’t go down the hatch too easily.

Time and again, she slipped back into the calm sea and emerged with a rockling, saithe and, once, a fat lumpsucker. Occasionally small eelpouts were snaffled in the water but with the rocks close by, and perhaps because it was warm and sunny, this otter seemed very happy sitting out and more often than not I could see her clearly.

I had grown up with Henry Williamson's Tarka the Otter, dreaming of their slick fluidity as they slipped between land and water. I never dreamt that it would be so easy to see one. Now, almost two hours later, the otter was swimming right below me, turning over rocks and letting out a tiny stream of bubbles. I stayed still and abruptly she climbed out and disappeared into the wood behind me. She was off to find fresh water, to rinse the salt from her coat. It had been a perfect morning for both of us.