A 57-year-old famed British explorer who was dropped by helicopter into Papua New Guinea three weeks ago so he could find a lost tribe of headhunters has disappeared.

Benedict Allen, who was supposed to be in Port Moresby on Sunday to take a flight to Hong Kong, has no phone or GPS device, and has not given evidence that he is around. He was insistent on looking for the Yaifo tribe, one of the few remaining anywhere who have no contact with outsiders and live in the jungles of East Sepik, where roads or navigable rivers are non-existent.

Allen’s agent, Joanna Sarsby, stated:

His wife Lenka has not heard from him. She is very worried. He would never miss something like the Hong Kong talk unless something had happened. He is a highly experienced explorer, very clever and resourceful and adept at surviving in the most hostile places on Earth, and he would never give up. He may not be a young man any more but he is very fit.

He was trying to reach the Yaifo people, a very remote and reclusive tribe – possibly headhunters, quite a scary bunch. Goodness knows what has happened. I just imagine he might have been taken ill or is lying injured somewhere, perhaps with a broken leg, and maybe being helped by locals. He never takes a phone with him – he believes in living like the locals. For him not to come back is really odd.

Allen, who has recorded six TV series for the BBC, married his wife in 2007; they have three children under the age of 10. Allen made the first documented journey of the length of the Namib Desert and is reportedly the only person known to have crossed the full width of the 1,000-mile Gobi Desert only using camels. Allen has reportedly traveled for longer alone in rainforest than anyone else alive. The Daily Telegraph listed him as one of the top ten British explorers of all time.

Allen’s last blog post on his website read:

The Yaifo are one of the last people on the entire planet who are out of contact with our interconnected world. I’m hiring a helicopter to drop me off at the abandoned mission station, Bisorio – a forlorn place. Last time, the Yaifo greeted me with a terrifying show of strength, an energetic dance featuring their bows and arrows. On this occasion who knows if the Yaifo will do the same. Nor do I have an obvious means of returning to the outside world, which is somewhat worrying, especially at my advanced age.

Either I must paddle down river for a week or so – or enlist the help of the Yaifo, as I did last time. So, if this website or my Twitter account falls more than usually silent – I’m due back mid-November – it’s because I am still out there somewhere. So, don’t bother to call or text! Just like the good old days, I won’t be taking a satellite phone, GPS or companion. Or anything else much. Because this is how I do my journeys of exploration. I grow older but no wiser, it seems.