A scene shows people standing outside a TV shop named Magpie Electrical. This is the name of the television shop used in The Idiot's Lantern (2006) with the 10th Doctor and Rose.
Under the monks everyone wears blue overalls, just as they do in Orwell's 1984.
The Ministry of Truth van and the aliens' pyramid in the middle of London are references to Orwell's 1984, where the ministries were huge, pyramid-shaped buildings.
Magpie Electrical is also seen in Season 5 Episode 2, The Beast Below. Amy passes by it when she enters the tent covering the opening to the lower workings of Starship UK.
This episode is the third part of a three-part story (Extremis, The Pyramid at the End of the World, The Lie of the Land).