Deep in the rainforests of south-east Peru, the Mashco Piro are believed to be the largest uncontacted tribe on Earth, but they've recently been seen more and more on the banks of a nearby river.  

Logging concessions have squeezed their territory in the last twenty years, but the images showing dozens of tribe members could help overturn that. So who is best placed to help the Mashco Piro through that?

• Featured: Jonathan Mazower, Survival International
• Producers: Joanna Crothers, Madeline Hanger