Guest Stars Matilda Ziegler as Christine Miller Neil Maskell as Martin Moran Mark Benton as Professor Elias Blackwell Jane Lapotaire as Fiona Deakin-Jones Cavan Clerkin as Craig Nigel Betts as Mike Brennan Alison Lintott as Caroline Moran Colin Tierney as Michael Sweet Joseph Long as Dmitri Zavos Keith Bartlett as DCI Harris Khalid Laith as Ahmed Ansari Maggy Sherif as Narima Ansari Uncredited Nick Turner as C.I.D.