The London Tube Map fundamentally lacks key mapping elements such as topography and urban detail, but what it does is encourage a mental map of London, one that exists inside the passenger’s head allowing them to traverse the city, much like London’s cabbies achieve when studying The Knowledge.

The beauty of its design, as Caroline Roope points out in her excellent book, The History of the London Underground Map, is that it’s as much at home hanging on the wall of a modern art gallery as it is stuffed in the pocket of a London commuter.

The flexibility of the Tube Map, and its capacity to grow and adapt along with the city it represents, have inspired numerous interpretations of what it means to traverse the metropolis.

There are plenty of differences between Harry Beck’s first effort and the map we know today. An extra 200 stations have been added, along with additional lines, the latest being the Elizabeth Line with the addition of charging Zones and an index.

Beck’s original had station names in capitals, as was customary at the time, every station is marked with a ‘blob’, and interchanges are shown with multiple circles, even so, the spirit of the modern map is detectable.

Today in a belated acknowledgement of Beck’s genius the modern map has this description: “This diagram is an evolution of the original design conceived in 1931 by Harry Beck”.