7. Previous Companions
The Doctor's travelled with so many companions that every now and then, of course he mentions a few. In Series 7 alone, Tegan was referred to as "a gobby Australian" in 'The Crimson Horror', Susan was mentioned in 'The Rings of Akhaten' and Amelia Willams was credited as the author of 'Summer Falls' in 'The Bells of Saint John'. But perhaps more subtle in 'The Bells of Saint John' was the look on the Doctor's face when Clara tells him, "People always have plans", perhaps evoking the memory of Amy saying in her first episode, "People always say that". Subtler still was the Doctor's quote in 'Fear Her', that "You dismissed it, because what choice do you have when you see something you can't possibly explain?" This was a reference to Susan mentioning in
An Unearthly Child that "Their minds reject things they don't understand." Hey, the Doctor even mentioned in 'Fear Her' that he was a parent once. Also from Series 2, the Doctor used his former companion Jamie McCrimmon as an alias when pretending to be Scottish (a Scottish actor playing a Gallifreyan with a Southern English accent pretending to Scottish... wrap your head around that one). Oh, and it was Jamie that gave him that pseudonym, John Smith, that he's been using sporadically ever since. Now you know.