The past two Christmasses have seen new Agatha Christie adaptations from Sarah Phelps. They’ve been sensational, not only refreshing the Christie brand for a new generation (while keeping the period stylings and Christie twists and turns), but also marking Phelps out as one of our very best screenwriters. And The There Were None and Witness For The Prosecution were must-watch television events. We knew that this year’s Christie adaptation – also from Phelps – was to be Ordeal By Innocence. Now we know the cast.