Moth/butterfly ?

Moth/butterfly ?

Observation - Moth/butterfly ? - UK and Ireland. Description: Medium size moth/butterfly seen on the grass, did not move as we approached. Black background with white splodges & bright yellow background with black splodges on the wings

Medium size moth/butterfly seen on the grass, did not move as we approached. Black background with white splodges & bright yellow background with black splodges on the wings