Kuching sheds its skin awfully quickly. The capital of the Malaysian state of Sarawak has all the noise, clamour and clutter — motorbikes scuttling, cars growling, shops spilling onto the street —that comes with any sizeable city in the Far East. But as the car passes through the outskirts, the jumbled homes start to press the road with less urgency and the jungle steps in instead: deep, green, all-encompassing. Once upon a time, Borneo was like this in its entirety; all 287,000 square miles of it, one vast stretch of 140-million-year-old rainforest. But some things don’t change. Batang Ai National Park, 150 miles south-east of Kuching, is one of them.

And here, amid the dense growth, my journey into the real Borneo is gaining pace. I’m seeking the Dayak, the indigenous people of the island, who have long lived a simpler, less intrusive life among the boughs and branches. Specifically, I’m looking for the Iban, the Dayak tribe who eke out their existence in the backwoods of Sarawak and Sabah, their homes seamlessly slotted into the jungle, rather than overpowering it.

Batang Ai Reservoir fades behind me, the Delong River pulling me east in a wooden boat — more an extended canoe than a ferry — so low to the brown-green water that it seems likely to be swallowed by it at any second. The motor snort s and coughs every time the pilot has to swerve us around a floating log or shallow section or through a patch of rocky rapids. There are shrill calls and rhythmic beats from the canopy, hornbills and woodpeckers at work. And the trees seem to crowd ever closer with each mile, as if the jungle wants to pluck me from my damp seat and hold me close.

It will have its way. After 90 minutes, we pull ashore at what seems the smallest of gaps in the foliage. And there it is in a clearing: the Nanga Sumpa Longhouse. Suddenly, there are people. Lots of them. Hands shaken, broad smiles, children flitting around my feet with that mix of curiosity and mischief that seems inherent in the under-fives. There are smatterings of English, a warm welcome, my bag lifted from my back and carried ahead.

The elongated structure clings to Borneo tradition so impressively that, momentarily, I stop and stare at it. On first impressions it looks a mile in length, raised up on stilts to protect it from flooding. While this might be a visual illusion, it’s still a mighty construction. One main corridor ebbs into the distance. There are chambers off it at neat intervals, perhaps 40 in total, each one a set of rooms that accommodates a family. There are cooking smells and there’s conversation, a giddy burble of voices. And as the day fades, the whole longhouse empties into the communal area for sitting, eating and talking.

It would be easy to romanticise all this as some 15th-century charade, shielded from 2016 by the thick treescape. That would be a misrepresentation. Even here, the 21st century has found a way in. In one family unit, Taylor Swift lip-synchs silently on a muted television. In another, several young men are watching Premier League football, their enthusiasm undimmed even when the signal struggles to pierce the chlorophyll umbrella above. And when I slip into sleep in the adjacent Nanga Sumpa Lodge — exclusively for tourists — I do so in a comfy bedroom with clean linen and an en-suite bathroom. But the jungle stands firm. And as I drift off gently amid its myriad shrieks and howls, I feel utterly removed from the city and its paltry concerns.