This question has tantalised explorers for centuries. This level of isolation and deep rooted connection to the past is a very romantic and, for some, unimaginable notion. But discovery brings with it huge problems for the people so perhaps there are more important questions to answer: how best to protect their ancestral forests and should we go looking for them in the first place?

Images from near the Brazil/Peru border surfaced this week that appear to show an unknown group of native Amzonians covered in body paint and firing arrows at the aeroplane. Clearly this tribe didn’t want their isolation shattered and who can blame them. Discovery can mean conflict, exploitation, disease and, ultimately, extinction.

The Brazilian government say they took the photos to prove that isolated tribes live in the region, on both sides of the border.

This has prompted the authorities in Peru to take measures to protect them including a promise to stop loggers, who are often the first to encounter tribes, encroaching on their land.

According to Survival International, a group that supports tribal people around the world, there are an estimated 500 isolated indigenous people in the region.

Survival International's director, Stephen Corry, said: "This is a positive first step from the Peruvian government, but it must act fast.

"It must stop the logging, remove the loggers and any other invaders from the uncontacted Indians' land, and ensure that no-one else enters in the future."

The Peruvian government has sent a team into the forest to discover whether the tribe has migrated from Peruvian lands because of logging encroachment. This is significant progress because until now they have been reluctant to acknowledge the existence of uncontacted tribes or protect new tracts of land for them.

Marco Tulio Valverde, who advises the regional government, said: "We haven't determined if there are three different groups or only one, nomadic, which has been displaced.

"They only hunt, gather and fish. They don't farm, but they know fire."