A cute but insubstantial slice of nostalgia-who - not that it’s lack of meatiness matters. This sketch is unashamedly and justifiably aimed squarely at the fans. Within its short run time it doesn’t have to go anywhere or do anything. It’s a wry few minutes comparing, for the first time, the worlds of classic and modern Doctor Who. Seeing Peter Davison’s 5th Doctor back alongside Tennant’s incumbent 10th is a mind bending sugary treat. Once you have that you don’t need much more than some little gags.