This is the Britain's largest and most spectacular butterfly, with a wingspan that may reach 9 cm. It has creamy-yellow wings with heavy black veins and blue margins. The hindwings have distinctively long 'tails' and a red spot.

Note that any sightings in Leicestershire and Rutland are almost certainly the result of reared adults being released.

Please provide a photograph to support your record.

Wetlands and reedbeds - favouring areas where the sole larval foodplant, Milk Parsley (Peucedanum palustre), grows

Adults usually fly between May and July, peaking in mid June. Sometimes, a second brood may emerge from the end of August to mid September.

The sole larval foodplant Milk Parsley (Peucedanum palustre).

The resident British population (subspecies britannicus) is only found in the open fens and marshes of east Norfolk where its foodplant Milk-parsley (Peucedanum palustre) grows.  The species was once more widely distributed in the fens of Norfolk, Suffolk and Cambridgeshire. Any records from elsewhere in Britain almost certainly result from the release of adults in the local area rather than natural migration.

Unknown as a naturally ocurring species in Leicestershire and Rutland (the food plant is absent). Any records in our area are almost certainly the result of released adults.

The British Swallowtail, Papilio machaon britannicus, is a rare subspecies now confined to the Norfolk Broads. Very occasionally migrants may arrive in Britain from the Continent, these are subspecies gorganus and will use a variety of foodplants such as Wild Carrot.