Shortened version...
Battery power travels down a thick brown wire to the light switch (always alive and unfused), out from there via a white wire (ignition live and unfused) to the ignition coil and fuel pump to the fusebox where it turns to green (meaning ignition live but fused) to all the other toys like radio, wipers, washers, fuel gauges, heater etc.
Red means lights that are on whenever the switch isn't off (sidelights, numberplate light, dash lights via a tiny square switch under the dash) and are unfused except for the later cars. Blue wires mean headlamp bulbs. Black is earth or on early Minors it means every bleedin' wire since the cotton coloured braiding fades and then all falls off to leave the black PVC underneath.
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