There is much that is typically Breton about Hervé Berville: his first name, the fact he learned to play the accordion as a child. His grandfather (97) is one of the best-known farmers in the Côtes-d’Armor district of northwest France.

The 29-year-old deputy in the National Assembly grew up in a left-leaning, Catholic household, typical of Brittany. At Sunday lunch, the Bervilles and their five children talked about politics and social issues. Hervé won 64 per cent of the vote in the 2017 election because, he says, everyone in the area knows him ...