10 Small Details You Only Notice Rewatching Doctor Who

One of the calling cards of Russell T Davies' first go around was his tendency to leave a trail of breadcrumbs throughout each series, all leading to a huge reveal in the final episodes.

It started with the multiple appearances of "Bad Wolf" in Series 1, then the regular mentions of Torchwood in Series 2, Harold Saxon in Series 3, and the various disappearing planets in Series 4 – capped off with the ominous prophecy "He will knock four times" in the 2009 specials.

It's much easier to spot these clues when you know what's coming – some of them are so subtle that you definitely need a rewatch to clock them.

In the Big Brother house in Bad Wolf, there are prints on the wall that look suspiciously like Dalek bumps, foreshadowing their arrival later in the episode. In Series 4, Silence in the Library shows a drawing of a blonde woman and a wolf on the wall of CAL's house – a very subtle hint about the impending arrival of Rose Tyler.

Our favourite though can be found during Series 8's Flatline, where Missy is sat in front of a door that bears a cutout of a Cyberman's eye.

It's a very dark, very brief shot, so there's no way of knowing this was teasing the Cybermen on your initial viewing of the episode.