Simon Reeve has trekked through jungles in Burma, Borneo and Colombia, but none, he says, is as "sticky and bitey" as the Congo rainforest. His irritation with the inhospitable terrain is etched on his face as he wades through swamps during the first episode of his latest TV series, Wilderness with Simon Reeve. Does the amiable travel presenter with the boyish charm and self-deprecating humour ever throw a wobbly?
"There's some careful editing involved," he jokes, adding: "I don't lose my temper, but I'm definitely a grumpy middle-aged bloke. However, there's never a point when I forget I'm bloody lucky to be doing this. I've worked for the minimum wage, I've been on the dole – I know I'm lucky to be doing this job."
In the four-part BBC2 series, Simon, 51, heads to some of the most remote landscapes on earth – what he describes as "the last great wildernesses". As someone who has covered all four corners of the globe, visiting more than 130 countries over the past 20 years, he should know. Accompanied by a small TV crew and a medic, he travels 500 miles across the dense, tropical forest of Congo; voyages through the crystal-clear seas and verdant islands of the Coral Triangle in the Pacific Ocean; treks across the mountains, ice and wild grasslands of Patagonia in South America; and tracks wildebeest with the San, the indigenous people of the Kalahari Desert in southern Africa, an "awe-inspiring" experience that took him out of his comfort zone.
"I'm from Acton, for goodness' sake," he exclaims at one point. The desert trip was his highlight of the series, which was 13 years in the making, from conceiving the idea to filming it in 2023.
Knowing that it would be "physically knackering", Simon, who lives in Devon with his Danish-born wife Anya and their 12-year-old son Jake, had to do some serious training. "I was running around Devonin the wilds, chased by my two dogs, wearing a 15kg weight vest and getting some very funny looks. It's not the greatest of looks for a middle-aged man," he says.
The London-born adventurer, who began work as a post boy at the Sunday Times and carved out a career as an author and journalist, having left school with no qualifications, says he has a "personality type" that requires his life to have purpose and meaning. "If I've got my mini-mission, a project, a plan, something to aim for, that gives me a 'why?' And sometimes, when I've got there, I can have a sense of annoying anticlimax: 'Oh right – what now?' "I love the unpredictability," he continues. "That's the aspect of the journeys that I'm probably most addicted to, and I miss that when I return. But I've been doing this long enough to know that the trips aren't my normal. That's not what I was born to do. My normal is being a dad and a husband and playing my part in the family."
"Years ago, I had a proper wake-up call," he adds. "I'd just come back from a journey around the Tropic of Cancer, and I'd barely had time to take my shoes off and I had to rod out the sewers."
How does his wife cope with his absences – and returns? "You'd need to ask her, but I think she copes better in some ways when I'm away than when I'm back, as she has another small boy to deal with!" he says. "I live a spartan experience when I'm away, so I find the clutter of modern life overwhelming when I come back. There's so much stuff everywhere. So many people."
Anya was a camerawoman before she met Simon, and the couple have worked on some programmes together. "So she knows they're not jollies, but also knows how exciting they can be. She doesn't want me to think I can get away with moaning about the lack of food or the state of where I've been staying.
"She'll say: 'Don't just give me that – you've got to tell me what's been amazing as well.’ Then I’m like: 'Okay, darling, fair dos.'"
When he's away, a week can feel like a month, he says. "After a day, I'm really missing my lad, but he's barely noticed I've left, which is annoying," he says with a smile. After all, he reasons: "I'm not a squaddie going off on a six-month tour; I'm a TV presenter poncing off for a short time and then I come back.'
Simon is looking forward to a family trip to Spain, before his son reaches an age when he realises that "he doesn’t have to go away with his boring parents". But professionally, he's yet to decide where he's off to next. "I've got lots of ideas, but nothing on paper," he says. "I love going back to places I've already been, but secretly, between you, me and the readers, I'd love to go somewhere new as well."
Wilderness with Simon Reeve is on BBC2 on Sundays at 9pm and is also available on BBC iPlayer.