Transport for London tell us that "The original tube map was created by Harry Beck in 1933. He was an Underground Electrical Draughtsman. Most maps emphasise distance and geographical accuracy. But Beck based his map on the circuit diagrams he drew for his day job. He stripped the sprawling network down to a neat diagram of coloured criss-crossing lines.
Beck’s revolutionary design, with certain modifications and additions, survives to the present day. You can find out more about Harry Beck and his world-famous map at the London Transport Museum.”