Scilly season: Tresco is more reminiscent of the Caribbean than Cornwall

All is quiet: Tresco offers a symphony of natural sounds - but perhaps most memorable is the sound of the swishing agapanthus

There's something about arriving by helicopter that makes a holiday feel special. (Not that I've done it before – and now the regular service to Tresco has been suspended, its financial future unclear, I may not again.) The exhilaration of rising slowly from the ground at Penzance, swooping over Land's End and soaring into the great blue yonder – next stop America!

Then a tiny archipelago appears – 500 islands, of which only five are inhabited – and you can't quite believe what you are seeing. White-sand beaches, emerald fields and purple moors, all dropped like gems into a turquoise sea more reminiscent of the Caribbean than Cornwall. I must be dreaming, I think. But, glory, this is where we land.

Unique among the Isles of Scilly, Tresco has been leased by the Dorrien-Smith family from the Duchy of Cornwall since 1834. The family owns everything – the shop, pub, art gallery and all the accommodation, including the smart new Sea Garden Cottages, where we stayed. It may sound old-fashioned but the result is that immense care has been taken over every detail – and once I'd seen the view from our tastefully appointed cottage, with its comfortable terrace and pristine lawn overlooking a perfect little bay, I was sold.

On Tresco, it seems that everyone you meet tells you, with a seraphic smile of contentment , that they have been coming here for 30 years – first as children, then as adults with kids of their own. The Boden-clad bankers-turned-fisherman, with their sun-tousled offspring; the families, more like ours, for whom a week here is the highlight of their year; the hikers and daytrippers off the boat from St Mary's; the staff who work on the island. They all glow with sheer delight at being here. Why? Because a week on Tresco is like Swallows and Amazons, the Famous Five and Treasure Island all rolled into one.

We were there in August yet the island remained wonderfully peaceful. It's a small place, two miles long by a mile wide, with plenty of holiday accommodation, but whenever we set off in search of another beach, we'd find ourselves making the only footprints in the talcum-soft sand.

At the island's sheltered southern end, the landscape is more tamed, especially around the imposing Abbey, where the Dorrien-Smith family still lives. Here, the botanical gardens, founded in the 19th century, include exotic plants from around the world, as well as a touching collection of figureheads recovered from ships wrecked over the centuries.

These days, Tresco is a carefree, miraculously car-free place, with only battery-powered buggies to ferry luggage around, so children can ride bikes and explore in freedom and safety. To neurotic urban parents, it seems positively pre-lapsarian. And if your little darlings tire of cycling, try kayaking – ours loved drifting about the bay counting starfish.

Perhaps the thing that really stays with you is the quiet – a quiet made up of a symphony of natural sounds: bird calls, waves, the swishing of the blue agapanthus that covers much of the island – a heavenly murmur used to great effect in Joanna Hogg's acclaimed 2010 movie Archipelago.

After days spent cycling, kayaking, fishing, walking or simply gazing out at the sparkling seas, we'd retire to the relaxed atmosphere and deliciously fishy menu of the nearby Ruin Beach Café (recently the recipient of a Gold award from Condé Nast Traveller). Our toast? "Here's to joining the ranks of 30-year Tresco veterans with seraphic smiles on their faces." Hell, we'd even be prepared to come by boat.

For more about Tresco, including prices and travel information, see tresco.co.uk. First Great Western runs direct train services from London Paddington to the south west; see firstgreatwestern.co.uk

More UK island adventures

1. Explore the Outer Hebrides on a seakayaking and camping trip, discovering 5,000-year-old stone circles and deserted beaches where you can bed down under the (almost) midnight sun (wildernessscotland.com)

2. Rathlin Island, a dramatic chunk of basalt rock, is home to Northern Ireland’s largest seabird colony. Spot puffins, kittiwakes and razorbills from its vertiginous RSPB reserve (rspb.org.uk)

3. Take a circular walk around the rugged Welsh island of Anglesey, a 125-mile route taking in Roman remains, sand dunes, sea cliffs and waters populated by porpoises (visitanglesey.co.uk)

4. Go wild-camping in Guernsey. Stay in a tipi, safari tent or bell tent, set on a hillside above the beach. Learn bushcraft or just kick back in a hammock (wildguernsey.wordpress.com)

5. Just three miles long by one mile wide, the Bristol Channel island of Lundy is small but powerful; its waters host England’s first Marine Conservation Zone, a hub for birdwatchers and snorkel safaris (lundyisland.co.uk)

6. Learn to angle from a sea kayak in the deep coves of Jersey. Practise paddling into optimum spots, anchoring, fish handling, pattern fishing and how to read water conditions (jerseykayakadventures.co.uk)

7. Brownsea Island is brilliant for young families. Go wildlife spotting on woodland trails or take guided walks geared to kids across wetland and heath (nationaltrust.org.uk)