We had been introduced to our guide, Gavin Ford, at the tiny airport in Maun, the gateway to the Okavango. Resplendent in khakis ironed with creases sharp as knives, he looked every inch the dashing, tanned adventurer of your safari fantasies. Here was someone you suspected had looked down the mouth of a lion and lived, but was too modest to boast about it.

The Okavango is one of the world's great natural phenomena - a series of permanent and fleeting waterways and floodplains, which occupy an otherwise sandy corner of northern Botswana. The word delta is something of a misnomer as it is completely landlocked. This unique landscape is the result of a collision of the mighty Okavango River, which rises in the highlands of Angola to the north, with the sands of Botswana. With nowhere to go, the water fans out into a complex web of rivers and streams, which escape via fault lines underneath the surface. The annual flooding, which begins in March, changes the landscape dramatically - the vast plains fill with water and vehicles are rendered useless, the best way to navigate the myriad waterways and lagoons being by traditional mokoro or dug-out canoe.

The base for our stay, Baines' Camp, was a perfect example of the small-scale experience for which Botswana is becoming known. Named after the 19th-century naturalist and painter, Thomas Baines, the lodge is located in a private 1,225-hectare concession on the southern edge of the Okavango on the Boro River. The plot is also less romantically referred to as NG32. Just over a year old, Baines' is best described as rustic luxury - its five separate thatched guestrooms are built on elevated platforms that spider out from the main lodge. It all gazes out on to a permanent lagoon inhabited by hippos that loll submerged, emitting plumes of water and deep guttural snorts.

But for all its contemporary safari-chic, at the heart of Baines' is something much more ordinary. The walls of camp are constructed from 150,000 tin cans collected from Maun, which have been stacked on top of one another and rendered with elephant-dung plaster. The camp is one of several lodges in the region that employ local people from the communities bordering the reserve. At night you can roll your bed out on to your veranda and sleep under a twinkling blanket of African stars, listening to the sound of the bush.

We were in extremely good hands. Gavin was a veteran with more than 2,000 safaris under his belt. He approached the bush as a great open-air classroom. Everything had a story, related with infectious enthusiasm. Elephant dung became a fascinating link in the delicate ecology, while he explained the importance of the small islands formed by termite mounds. These are a vital refuge from the floods and form the foundations for many of the leadwood, merula, acacia, ebony and palm trees that give the Okavango its unique topography. A bullfrog or chameleon was given the same treatment as a hippo or an elephant. A particular passion was reserved for the birdlife - a colourful array of 450 species including the woodland kingfisher, whose electric blue and black plumage could be seen as it flashed between trees. Gavin could barely contain his glee when Mother Nature obliged in one impromptu biology lesson - he cut into a green fig that revealed a seething mass of tiny moving specks, wasps waiting to burrow through the skin to escape.

"Every sound counts," he would say, cutting the engine in a night drive so we could soak up a chorus of mating frogs - a cacophony of purrs, croaks, whirrs and whoops. "This is our morning traffic," he proclaimed as we passed herds of giraffe and zebra as we set off early one day for the landing strip. One of the best ways to get a true feeling for the vast empty spaces of the delta, which spans an area the size of Wales, is to see it from above. As the helicopter swooped low, rivers and pools strewn with lily pads sparkled like ribbons. A sitatunga (an amphibious antelope) pranced over the papyrus marshes, while pools of hippos looked up disturbed by the thwack-thwack of the propeller. You could even see the fish as they wiggled through the crystal-clear water below.

During our stay we were also introduced to Jabu, Merula and Thembi, orphaned elephants who live in the bush near Baines' Camp with their American "guardian" Doug and his wife Sandi. On a three-hour walk through the bush, we were invited to touch and feel their thick skin as they sauntered languorously along, tugging at bushes as they passed. But that could not compare with our first encounter with a herd of wild elephants. Almost surrounded, we sat and watched as they lumbered past, more than 50 cows and their calves, their hulking shapes melting into the trees beyond like ghostly apparitions in the twilight.

Most of the time it felt like we had the animals and the bush to ourselves. Our lasting memory came one afternoon the day before we left. Spotting a female leopard as it lounged in the afternoon heat on the branch of a merula tree, Gavin pulled up and we sat transfixed as she lay tail and paw hanging down in National Geographic pose. But she drew the show to a close as she sprang down the tree in one graceful action. It seemed she was heading straight for us. Our hearts beat faster. Was this to be our all-too-close brush with the wild? We need not have worried. Gavin reached not for the rifle on the seat beside him, but his camera, and as he clicked, could just be heard to mutter under his breath, "You beauty."

The writer travelled as a guest of Abercrombie & Kent (0845 0700 611; www.abercrombiekent.co.uk). Five nights at Baines' Camp starts at £2,239 per person based on two sharing, including return flights, transfers, full-board accommodation and all game drives. Gavin Ford's daily rate is £295