Lamu itself is hardly a secret. Prince Ernst of Hanover and Princess Caroline of Monaco spend part of the winter in fashionable Shela, where Europeans are busy restoring the old Arab houses bought for a song from locals. And the lovely Peponi Hotel cossets minor royals, film stars and those who like to wear a linen jacket to dinner.

Some Shela residents bravely tackle the three-hour walk along the beach to Kizingo, but after arriving hot, red and weary, they usually vow never to do it again. That is just how we regular guests like it. Kizingo ticks all the boxes for a holiday hideaway: there are only seven bandas (simple palm-thatched cottages with walls of woven Pandanus), set in dunes just yards from the sea; it has a convivial bar and restaurant; and the hosts, Louis and Mary Jo van Aardt, have that rare ability to make visitors feel they are part of the family.

Guests wake each morning to see dhows sailing by, their shark's fin sails fat with wind. The beds are king-sized and romantic, draped with mosquito netting, and there are shady verandas to while away the hot afternoons.

In the three years since it has opened, word about Kizingo has quietly spread, attracting like-minded guests: people who enjoy good company, hate piped music and contrived entertainment, and whose idea of holiday bliss is to lie in a hammock reading a good book.

That is not to say there are no adventures to be had, effortlessly organised by the van Aardts. Mary Jo is on a mission to improve the schooling and water supply in the district, and only needs a glimmer of interest from the guests before they are organised on a trip to the mainland to see the work of the Kipungani Schools Trust.

She hires rickety old bikes from the locals for guests to pedal erratically through the cotton and maize fields, down sandy lanes shaded by cashew, mango and baobab trees. It is a rare opportunity to see a village in Kenya.

Louis leads adventures of the watery kind: north to fly-camp on remote islets and explore the ruins of Pate, once an important Arab trading port; south to snorkel on a reef that is alive with fish and, between November and April, dolphin. There is something life-enhancing about plunging into the clear blue sea after a pod of dolphins, watching them duck and dive, spiral and sprint, and flip along on their backs as if to say: "Hello, look how clever I am."

They come close, but never too close, and there is constant chatter, clicking and squeaking. They are probably saying how slow and useless we are at swimming, even with those big flippers.

Apart from taking a couple of planes and a speedboat to get to Kizingo, guests can feel good about leaving only a small footprint. The lodge is built on land rented from Kipungani village, the power is solar, and shower water is recycled to grow plants and stabilise the dunes. It provides work for villagers, buys fish and vegetables from local farmers, and supports two island schools and other community projects.

But Kizingo's enduring appeal is not its eco-credentials, but the way it encourages guests to relax and slough off the trappings of the West as the days go by. Men swap linen trousers for Beckham-style kikoi skirts and the women abandon the make-up box and the hairdryer.

Around the dinner table, set on the sand beneath a zillion stars, the only sounds are the lapping of the sea and happy, carefree laughter as Mary Jo recounts another of her endless stock of shaggy-dog stories about the family's adventures in Africa. At times like this, the stresses of 21st-century life seem a very long way away.

أ‚آ·  Kizingo can be booked direct (00254 733 954770, www.kizingo.com); double room US$300 (أ‚آ£175) per night, full board. The Ultimate Travel Company (020 7386 4646, www.theultimatetravelcompany.co.uk) offers a week at Kizingo from أ‚آ£1,100, including flights from London to Lamu via Nairobi with Kenya Airways and boat transfers.