Mind the gap has been part of the London Underground since the late 1960s, created as a short recorded warning for curved platforms where a visible space opens between train and edge. Recordings have been voiced by different announcers over the decades and the phrase has become a souvenir slogan, printed on posters and merchandise far beyond the Tube. Online, the short announcement is reused as an instantly recognised London cue, borrowed for travel edits, parodies and memes about British public transport.