Addu Atoll is made up of four islands linked by a causeway – which means there's lots more to do than lie on a beach all day, says Nigel Tisdall.
It's 6.45am in Addu Atoll and a spotted eagle ray is gliding nonchalantly past the steps of my over-water villa. Its wings flap gently in the warm, shallow waters that are so clear they seem to magnify the peaceful garden of delights below. Here comes a parrotfish in a fetching psychedelic number, bowling along on its dawn patrol. And there's a posse of snappily striped angelfish, hurrying by as if just back from an all-night party.
Spared the worst ravages of the bleaching that has dulled the coral in other parts of the Maldives, the seabed here is bejewelled with flashes of blue, green and purple. As the sun gains strength, the lagoon surrounding me fills with an immense calm. It is 82F (28C) and you know it's going to be another classic day of clear blue skies, sensational snorkelling trips, siestas on the daybed, then dinner on the beach with rows of candles decorating the sand.
So far, so very high-end Maldives – except that down here in Addu, the southernmost atoll in this 500-mile island chain, the holiday experience is refreshingly different. Traditionally, a trip to the Maldives has meant flying into the capital, Malé, then bouncing onwards as fast as possible to one of almost a hundred small and luxurious lily-pads that ceaselessly vie with one another to offer the most indulgent experiences.
Some islands are so small you can walk round them in 10 minutes, others proffer ridiculously OTT amenities such as an underwater restaurant, pretentious afternoon teas and wine cellars with bottles costing up to £38,000. Invariably there is a niggling fear that a week in the Maldives, however much you are in love, could well leave you feeling trapped, bored and overcharged.
But not here. Forty miles south of the Equator, Addu is rare in that it includes four inhabited islands linked by a 10-mile causeway that visitors are welcome to explore. By Maldivian standards it is populous, which means you occasionally see two motorbikes passing each other.
On the map the atoll's slivers of low-lying sand look like bones in an X-ray, enclosing a heart-shaped lagoon of 22 square miles. On its eastern side, Herathera runs for nearly three miles and is currently being developed as a 273-villa resort by the Thai hotel group Amari. Nearby, Villingili is almost two miles long, home to 132 villas run by Shangri-La. In Addu luxury doesn't just mean endless cold towels, three types of shower and butler service – it's about having lots of space, too.
In the south of the atoll lies its greatest secret – Gan, an airport served by scheduled 90-minute flights from Malé. Just as in the Caribbean, where it invariably pays to fly on to the lesser-known islands, so it is worth going the extra 300 miles to Addu.
As well as fabulous diving, waters pulsating with spinner dolphins and the thrill of getting far away from the rest of the world, there is the bizarre opportunity to take a not exactly taxing 20-mile cycle ride around part of the lowest, flattest country on Earth.
After a fortifying breakfast of coconut water, papaya and perfectly boiled eggs, I head off for a dreamy day biking around Hullabaloo, Notmuchtodo and Howfaristheloo. OK, they're really called Feydhoo, Maradhoo and Hithadhoo, but the islands of the Maldives are so enchantingly named (my favourite is Bodufenmadeboodhoo) I can't help wondering if Edward Lear got here first.
While other guests slap on sunscreen and settle in the hammock with their Stieg Larsson-loaded Kindles, I pick up a bike at Feydhoo jetty and head north. Taking a local guide is not essential, but I recommend it as you learn so much more.
Inaan, who teaches badminton at my resort, seems thrilled to show off his home turf, and even takes me to say hello to his mother and grandmother. As it's Saturday morning, they're besieged with children watching cartoons on television – just like back home.
"Life is more relaxed here than Malé," Inaan says, when I observe some local Muslim women have their heads uncovered. Addu has a history of independent-mindedness, even setting up a breakaway republic in the Sixties, and the staff in the resorts are noticeably cheery.
One reason is that they get to return to their families every night, whereas on other islands workers can be marooned for months. At the Shangri-La Villingili Resort, one of the strange pleasures to accompany your sunset cocktail is the sight of some of its 600 staff heading home across the lagoon on a ferry called Nice Weather.
Pedalling north, I note that the islands are at times so narrow that the sea is visible at both ends of the high street. The villages are neat and clean, shaded by breadfruit and mango trees with single-storey houses built from coral with corrugated iron roofs.
Following recent elections, many are painted with the colours of competing parties, while the shops go in for names that are entertainingly direct. One is called Local Veg, another Shawl and Hijab. Everybody smiles and waves at the mad Englishman out in the midday sun.
When we reach Hithadhoo, it's hard to believe I'm in the second city of the Maldives. We're through it in a flash, then double back to lunch at one of several garden cafés where islanders like to relax. There's no alcohol, of course, and a spicy fish curry with chapatis and a bottle of water costs all of £1.50 – in the resorts it can be 10 times that.
As we tuck in, Inaan tells me that the Maldivian idea of a slap-up meal is to have spaghetti or a burger. One advantage of visiting Addu is that many islanders speak reasonable English – not just the young, who learn at school, but older men too as result of the formidable RAF base established across the entire island of Gan in 1956. This operated for 20 years, with some 600 servicemen stationed here on year-long stints – along with one brave woman from the WRVS offering tea and sympathy.
Surprisingly, much of the RAF camp remains in good order, including the Astra cinema, kerbsides painted in black and white, and splendid gardens with mature trees and radiant flowers. Today, the officers' mess, complete with the old billiards table, is home to the Equator Village resort – the rooms now have windows with glass rather than the original wire mesh and mosquito screens.
Back then the airmen were not permitted to visit any other island, so amused themselves by swimming, boozing and playing golf on a small course by the runway. It's overgrown now, but the sport will return to Addu at the end of this year when a nine-hole course opens on Villingili.
With a perfect white-sand beach, three freshwater lagoons and some 17,000 coconut palms, this is the best island to stay on in Addu – and bliss for the softie cyclist. Every guest is given a robust green Hercules bike from India, and it's an utter delight to ride through the sun-dappled palms, waving to the geckos, watching the fish from the jetties, then heading off to the spa. Here nature has been so swept, pruned and debugged it's hard to believe that 50 years ago Addu was considered one of the loneliest postings in the world.
Once described as a place of "harrowing tranquillity" where "grown men weep with sheer geographical frustration", it's now a secret speck of heaven, tailor-made for the lazy tropical cyclist.