‘Almost forgot it,’ he told Innocent. ‘Thanks for reminding me.’

I could see doubt behind the guide’s eyes, but he didn’t object, just watched as Caleb strapped his knife, which came in a commando-style black rubberised sheath, to his thigh. When he drew it out the blade flashed blue silver. He waved it around a bit, trying to look as if he used it often, but the machete was obviously brand new and, combined with the lime-green hiking boots he was wearing, also clearly just out of the box, he looked ridiculous. I wasn’t the only person who thought so. I noticed Patience, dressed only in a vest top, tatty shorts and ancient trainers, watching his little display with the beginnings of a smile on her calm, round face. It vanished when she caught my eye.

The hike into the jungle started out easily enough, but Innocent was right; as soon as we left the established path the going got tough. It felt as if the impossibly lush vegetation was sprouting around us as we walked. And it was, I know, but what I mean is that I could almost see and hear and smell it pulsing upwards, reaching for the light. The day grew hotter, the air thicker, chewier. It smelled strangely like cooked broccoli. At one point I stepped over a moving line of bright green ants, each as big as a paperclip, some carrying leaves or bits of twig. Where were they going? Where were we, for that matter? There were no clearings as such, just patches of less dense tree-tangle. We had to push aside fronds and stalks and whole bushes to make progress, and despite the thick tread of my walking boots I slipped and slid when the earth beneath us became a reddish clay sludge. I wasn’t about to complain though, and not just because Patience, carrying a load that looked suspiciously heavier than mine, was just ahead of me much of the time, floating along with ease, even pausing to hold the occasional branch clear of our makeshift path, and she didn’t appear to have even broken a sweat.

With so much going on at ground level, as we pushed through the foliage I didn’t really have time to look beyond my feet. But we hadn’t been on the move long before Innocent paused, motioned for us to be quiet and pointed up at the canopy above us, indicating a group of brown and grey monkeys gathered among the branches.

‘Red colobus,’ he said. ‘Resting now, after early-morning feeding.’

I craned my neck to get a better look. The name made sense; on closer inspection their brownish backs were more a coppery red. They looked thoughtful up there, meditative almost, and their fur was improbably stylish, like a show-dog’s. Through the zoom lens of my camera I could clearly make out three young-looking monkeys dangling their legs over a thick branch, and closer to us still a bigger, older specimen sitting in the crook of a branch, leaning right back, with his hands clasped behind his head. If the first lot looked as if they were on a park bench, he was definitely kicking back in a sunlounger. I snapped a few good photos while we watched them; by zooming in I could fill the frame with individual faces.