David Walliams and Hilary Strong (Agatha Christie Group) approached Hilary Bevan Jones and Tom Nash (development producer) of Endor Productions with the idea of re-inventing the Agatha Christie characters Tommy and Tuppence Beresford.
Creating 1950s England led to filming in central and greater London, Essex, Buckinghamshire, Surrey, Oxfordshire, Kent, Hertfordshire, and Norfolk.