Azure blur: one of Tresco's dazzling beaches

Before Blur headline the closing concert for the London 2012 Games, Alex James took his family to the Isles of Scilly for a proper seaside holiday.

I'm all for bucket and spades, but many of our once-noble seaside towns struggle to compete in a world of cheap flights to perpetual sunshine. A shame, because there is nowhere in the world as pretty as Britain. A holiday here is always a gamble, though. Not just because the weather's iffy and the party has moved on elsewhere, but because the food is often still a lottery, and it's not cheap either. For many of us these islands remain relatively unexplored. I've been trying to visit Wales for years but never quite seem to manage it.

When I was of bucket-and-spade age, we always went to Cornwall for our holidays. We never got as far as the Isles of Scilly but they loomed large in family legend. My mother always said we'd go one day – and as my dad is turning 80 this year, I thought I'd take the whole extended family.

The archipelago lies across just a few miles of open water from Land's End. There are regular ferries and – for the next couple of months, at least – a helicopter service from Penzance. But I'd thoroughly recommend going by plane, because Land's End airport is the cutest in the world. The runways are grass and the ambience is more agricultural than jet set. The bacon butties in the terminal, if you can call it that, are works of art.

There were nine of us: me, my wife Claire, the five kids and Granny and Grandad. We filled the whole aeroplane (a Twin Otter). From the moment we boarded we left the world behind. Somehow, all of us crammed in and that flying tractor felt more glamorous than flying first class to Tokyo ever did. We flew to the biggest island, St Mary's: low, zooming along at 1,500ft, the kids all wide-eyed with glee. Their eyes grew wider still as we hopped on a rib to Tresco and bounced over the wave crests. We were eventually delivered to our cottage, along with our bags, on a golf buggy. There are no cars on Tresco. Maybe that's why it's like nowhere else on Earth.

Charles and Diana holidayed here. The Old Mill, where we were staying, is said to be a favourite of Pete Townshend from The Who. The first person I ran into when we went to the bike-hire shop was Oliver Spencer, the fashion designer. He dressed me for the Brits this year.

"Have you been here before?" said Oli as our children fiddled excitedly with bicycles and knocked things over.

"Never," I replied.

"It's our 18th consecutive year," he said. "Don't tell anyone how good it is, will you? It's supposed to be a secret."

It is a very special place: unforgettably pretty. Tiny green jewels of fields are tied with beaches and stitched together with hedgerows, then decorated here and there with nestling clusters of houses. The palms that flourish in the balmy microclimate lend a pleasant whiff of desert island-ness. The absence of cars promotes a feeling of safety; kids can roam free for the whole day, as I was able to when I was young.

Tresco has been under the stewardship of the Dorrien-Smith family – once known as the Lord Proprietors of the Scillies – for generations, and nearly every one of the 150 residents works to support tourism. It's only a mile long and two miles wide – but it's a whole world to get lost in. I didn't bump into Oli again for the rest of the week.

The Old Mill itself was wonderful. I spent much of my time fiddling about with an enormous Weber barbecue in the back garden where an English partridge sat on a clutch of a dozen eggs under a bush just outside the side door. Thrushes hopped in and out of the kitchen. There were swallows nesting under the eaves, and seagulls and gaudy pheasants all came to have a look at what I was up to. Birdsong filled the air from dawn until dusk.

My parents mooned about holding hands. There was always a sense of pleasant things in the offing. Riding bicycles to the swing park, throwing another couple of chickens on the barbecue, or sampling more of the many cheeses available at the shop and deli.

Cornish dairy products are one of the world's great culinary treasures. We undervalue them: clotted cream, traditional ice cream, artisan butter. Even such a commoditised, standardised, unloved thing as a pint of milk can be a thing of exquisite pleasure here. And the pasties really need a whole column to describe properly: unbelievable.

There are several restaurants on Tresco. Traditional and well-executed pub grub; wood-fired pizza in a recently opened and hopping joint called the Ruin Beach Cafe on the other side of the island from where we were staying; and the candlelit Flying Boat Club restaurant with good views of infinity, serving tickety-boo local, seasonal menus with a minimum of fuss and big dollops of hushed glamour.

By about the third day I'd hit my holiday stride: wearing the same trousers, no socks, having plenty of naps and feeling good. The kids would have been happy to spend the entire week in the spa. We fell into a blissed-out routine of pleasant nothings and sandcastles.

There was a bonfire party to which everyone was invited on the site of a hilltop Tudor fort, all the lights on the outlying islands in the cluster twinkling below and the stars blinking above. It was enchanting. This is what all seaside towns should be like: alive and kicking.

The rumour that the island band was playing at the pub on Thursday proved to be well founded. As Claire and I arrived they were steaming through a version of Franz Ferdinand's "Take Me Out" and blowing the roof off. The whole place was jumping like a Hogarth etching, faces twisted with glee, children dancing on tables.

I got stuck into some overproof rum as recommended by the barman, while the Amazon beauty dressed in Lycra standing next to me sank a pint of Guinness while punching the air and explaining that she and her crew had rowed over from St Mary's in a gig for the evening. Soon, I was surrounded by strapping girls in Lycra. Come back with us they said … come on …

It made Ibiza look dull.

At the swimming pool the next day, there was a buzz going around that at midday the tide would be low enough to walk across the channel to the neighbouring island, Bryher, which is even smaller than Tresco. All nine of us – the two smallest perched on parents' shoulders – made the crossing with the rest of the gang from the pool (their 10th consecutive summer here).

The calm was perfect and the sunshine brilliant. We had sardines for lunch on a terrace overlooking a lagoon at the just-refurbished-for-the-21st-century hotel, Hell Bay, which, I couldn't help noticing, houses a significant art collection of the St Ives School: Hepworths, Herons and so on.

A ferry took us back to the Abbey gardens end of Tresco. It was nearing the end of the week, but it still felt like there were lots of things I hadn't done. I could have spent a week in those gardens alone, among the exotic plants and the immaculate vegetable and flower gardens that flank the remains of an ancient abbey below the Dorrien-Smiths' house. There's a unique collection of figureheads from ships wrecked around the island, too.

The only place that I've been that comes close in feeling to Tresco is Mustique – but that is still utterly crass by comparison.

The island rumour mill was going 19 to the dozen as we got back to the shop to grab some dinner. The weather was about to take a turn. The gale reached a stonking 70mph, enough to knock my dad over, which he rather enjoyed. The place was, if anything, even more beautiful when it was taking a hammering from the elements, especially the next day when the wind had died but the sea was still immense. Watching the waves breaking over the rocks was mesmerising – a very good morning's work.

I didn't see anyone on a mobile all week. Tresco is not just an idyllic reminder of the Great British Seaside of 50 years ago; it's more than that. It's somewhere else altogether – a completely independent entity with its own unique and precious culture. Not just paradise on Earth, it's paradise in Britain.

But please don't tell anybody.

Travel Essentials

Getting there

Helicopters operate between Penzance and Tresco (01736 363 871; islesof scillyhelicopter .com); however, the service will come to a permanent end on 31 October. Skybus (0845 710 5555; serves St Mary's in Scilly from Penzance, Southampton, Bristol, Exeter and Land's End. By sea, Scillonian III departs from Penzance for St Mary's (ios-travel From St Mary's, Tresco can be reached by boat.

Staying there

Weekly rentals in a three-bedroom Traditional Cottage on Tresco start at £850, £1,475 in a Flying Boat Club Cottage, or £1,615 in a Sea Garden Cottage (01720 422849;

More information

Isles of Scilly Tourist Board (