The swallowtail, Britain’s biggest butterfly, last year had its worst summer since scientific counting began in 1976. What followed was potentially more catastrophic: the deepest and longest winter floods in living memory across the Norfolk Broads, which is the only place where this spectacular insect still breeds.
The swallowtail fixes its chrysalis low down on reed stems and there were fears that many would perish if submerged in flood water.
