The clarity of light in the Hebrides at dusk is often remarkable, as it was in Hough Bay on the Isle of Coll the evening I was watching the sunset on the crescent-shaped beach. All the better then to observe the three ‘fins’ (in fact the tail, dorsal fin and grotesque top jaw of a single plankton-feeding fish) which emerged from the sparkling water, about 50m away.

It was the first time I had seen a basking shark and, over the next 30 minutes, at least eight more sharks – each around five or six metres long - appeared, until the shoal spanned the length of the bay. One of the attractions of this sparsely populated island is that an explorer can relish the scenery in solitude, but this was an experience I wish I could have shared.

A growing number of basking sharks have been sighted near the Coll coast, which scientists attribute to the density of food. Now you don’t have to take an organised tour - visit Coll and its neighbour, Tiree, between late spring and late summer and you've a good chance of seeing one from land.

One of the least-visited of the populated Hebridean islands, Coll is a three-hour ferry trip from Oban, in Argyll. Limited boat services have ensured that the island has retained its outpost character (if you pass someone on the single-track road, it’s a requirement to wave and smile) but with work on a runway complete and flights to the mainland due to start in the new year, Coll could soon become a much more viable weekend destination.

Much of the island is an RSPB reserve, dedicated to the preservation of the coot-like corncrake, and the fragile coastal ecosystems in which it thrives. The society, which operates tours from its Totronald visitor centre, works with farmers to protect and increase the bird population, creating ‘corncrake corridors’ of longer grass around the fields as cover for when the migrants first arrive from Africa. As a visitor, you might see a corncrake, but you are more likely to hear it, and you’ll know if you have – their ‘crex-crex’ call is a horrible noise akin to long fingernails scraping a metal comb.

The island is captivating in spring, when it is carpeted yellow with iris and daffodils; and summer, when the light evenings go on forever, and the land is tinged the red and pink of the rocks and the heather, but autumn – when most visitors have gone – is the best time to experience the drama of the coastline.

It takes determination to reach Coll’s beaches, most of which are not accessible by road, but each is a find, from the tiny Gortan, in the west, where a wooden shipwreck is embedded in the sand, to Cliad, near the rough-and-ready golf course, where seals bask on the rocks and you might spot an inquisitive otter, and Breacachadh, where children can go rock-pooling in the shadow of two castles.

The beaches also present a chance for younger readers to explore the world of Katie Morag, heroine of Mairi Hedderwick’s popular children’s books, which are set on Coll, and while litter drifting onto the shore can occasionally be unsightly, it is collected regularly by volunteers from the island-based gap year charity, Project Trust.

For views, the dunes and cliffs around Feall (pronounced Foil) in the west and the rocks at Sorisdale at the east end are worth a walk, but the most imposing scene is from the peak of the island’s hill, Ben Hogh, where you can make out the shapes of the Treshnish Isles, including the distinctive ‘Dutchman’s Cap’ and off to Eigg, Muck, Rhum and even to Jura and Skye.

You can shoot geese (in season and by arrangement) or snipe at Cliad Farm, catch your own mackerel or collect mussels. Even your fuel can be locally sourced. Gordon, who can be spotted walking the dogs, or pottering around the village on his bicycle, is one of few residents who grew up on the island, and an expert on where to cut the best peat.

The easy alternative to doing it yourself is a night out at one of Arinagour’s two restaurants. The island’s population may only be about 200, but residents of entire cities are less fortunate in their choice of quality, affordable eateries. The cosy First Port (or Island Café) boasts an organic, fair trade menu that can include Thai and Chinese food, as well as traditional fare and (in season) the best game pie I’ve tasted. The welcoming fire is always lit and come what should be closing time, owners Pauline, Julian, Darren and Paula are more likely to join you for a night-cap than to throw you out.

At the Coll Hotel, which overlooks the bay, Julie and Kevin Oliphant have just installed a helipad in the beer garden at the request of frequent visitors. And it’s worth the trip: its Gannet restaurant has won national awards for its seafood, but visitors are warned to leave room for Julie’s desserts, the cheesecake in particular.

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