For 40 years, they've fought a jungle war for freedom. Alexander Groom meets one of the world's most isolated rebel armies.

A sound of gunshots filled the air as we clambered through thick undergrowth to a clearing. There, perched on a a steep mountainside surrounded by lush rainforest, was a breathtaking sight. Villagers charged around chanting in a state of high excitement.

The village leader, dressed in little more than a wooden penis koteka and a feathered hat, solemnly called everyone to attention. Then two men stepped forward to raise the outlawed national flag.

A wild pig had been slaughtered, and we settled down to a feast with spinach and sweet potatoes. Around us, a ragged bunch of men sat watching, smiling and looking on as they smoked the locally grown tobacco.

Armed with bamboo spears, bows and arrows, (as well as a few old AK47 assault rifles) 400 rebel fighters are hidden here in one of the remotest places on earth, the jungle highlands of West Papua. Some of the soldiers were dressed in old T-shirts and combat fatigues, but most wore little more than wooden kotekas (penis gourds), their hair and limbs decorated with garlands of leaves.