Iran begins public mourning for Ayatollah Khamenei

As allies and dignitaries gather, we'll ask what the funeral tells us about the country's resilience. Also on the programme, a major study of social media use and children's mental health from the research and policy group BrainWaves, suggests the evidence does not support a blanket ban for under-16s. We'll discuss their findings. We'll have the latest from Sudan as the UN once again sounds the alarm over developments in the conflict. And, as men are found to be twice as likely to ‘hit a wall’ in marathon running, we'll hear why over-confidence may be to blame.