Eddie Izzard pushes her body and sense of humour to the limit for Sport Relief as she takes on an immense challenge - travelling to South Africa to run 27 marathons in 27 days to mark the 27 years that their hero Nelson Mandela spent in prison. It is a gruelling, uplifting and hilarious journey through baking heat, high roads and hospitals - but can Eddie make it to the final finish line?

• Documentary