The two leads are excellent in their roles and Redmayne deserves particular praise for his portrayal of a serial killer who committed his crimes as if they were just an ordinary part of his professional life. People like Cullen and Shipman, medical professionals who killed hundreds of people, are just unfathomable to ordinary people because of the enormity of their evil and Redmayne captures the mundane manner of Cullen's crimes which, like Shipman's, seemed to be just something they did at work in the same way most of us decide to tidy our desk or have extra sugar in our coffee. This kind of madness is beyond ordinary comprehension so it must be very difficult to portray. It's done very well but I'm not sure we get any insight into what drives such people to do what they did. Chilling, indeed.
