Albie Woodington played young Alan Turing and Derek Jacobi played present day Alan Turing in Breaking The Code.
This episode marks the first appearance of Eoin McCarthy as Hugh Beringar, succeeding Sean Pertwee in the role.
This was the first episode of the series to air after the death of Edith Pargeter (a.k.a. Ellis Peters), the author of "The Cadfael Chronicles", on October 14, 1995 at the age of 82.
This episode is based on the sixth novel in "The Cadfael Chronicles", which was published in 1982.
This adaptation omits the supporting character Brother Elyas from the novel. His role is instead taken by Brother Oswin.