10 Doctor Who Easter Eggs Hidden In Plain Sight

10. Star Trek Under The Lake

In the ninth season of the revival, the Twelfth Doctor and Clara arrive on The Drum, a mining facility off the Scottish coast in 2119. The episode is a creepy ghost story, full of tension, ghoulish lighting and properly engaging hauntings. There are plenty of mysteries etched in every wall, yet one of the most fun, albeit gruesome images, is the mural of the sea monster devouring some hapless sailors.

The sailors have a distinctive yellow, blue and red colouring - exactly the colours of the original Star Trek uniforms. Yellow, for command. Blue, for medical and science. Red, for target practice.

The fearsome-looking creature is devouring one unlucky soul, which does not bode particularly well for the Doctor and Clara, nor the inhabitants of the base. They escape behind a locked door, one which bears the number 1701. Again, anyone familiar with Star Trek will recognise this number instantly as the registry of the USS Enterprise - no bloody A, B, C or D!