The changing a point in history plot has been used ad infinitum in all forms of sci-fi shows but I think that Russell T Davies' interpretation is one of the very best. Piper's character is a bit flat but I wonder if this is deliberate as it allows Catherine Tate's Donna to shine in all the peril the episode contains. Hard to believe that there was doubt about her character seeing as Tate was more famous for comedy back in 2006! This, "Planet of the Ood" and "Fires of Pompeii" stand out to me as some of Tate's best performances as Donna.
Of course the writing is tight and well-done and Cribbin's Wilf is always excellent too.
Of course the writing is tight and well-done and Cribbin's Wilf is always excellent too.