Joining Bridget Kendall to be noisy about silence are American conservationist John Francis, who chose to stop talking one day and didn’t speak again for seventeen years; Russian ice artist and explorer Galya Morrell, who has found that silence is an essential tool for survival in the North; and award-winning historian Diarmaid MacCulloch, who is interested in the tension between speech and silence that has existed throughout Christian history.

Listen to podcast at BBC Radio 4