A few shots of a couple "extra" speed Raleighs - black 1958 Sports FW 4-speed and green late-60s Sprite S5 5-speed.
It turns out that the FW and S5 are basically the same hub. Speed 1-4 are the same in each. The S5 gets its extra "top" gear because it has a non-drive side bell crank that allows movement from 4th gear (high) to 5th gear (top) by moving to the second sun gear.
By the late 1940s, it was apparent that derailleur-equipped bicycles were making serious progress in their ability to run multiple gears reliably. This was especially true of developments in bike design in France.
During the 1940s, Sturmey Archer debuted the FW wide-ranged four-speed hub. Sturmey also offered the FM medium-ratio four-speed and the FG four-speed with a built-in dynamo.
By the 1960s, Sturmey Archer was able to squeeze one more gear from the FW design via a non-drive side bell crank, creating a 5-speed hub. By this time, however, Sturmey Archer quality was beginning to decline.
Even Raleigh, a stalwart of internal gear hub use, had debuted derailleur bikes in the 1950s. By the late 1960s, even utility bikes, like the Sprite, were being offered in both derailleur and internal gear hub versions.
The S5 was the last "classic" Sturmey Archer hub of the post-war era.
The S5 would ultimately undergo several variations into the modern era, including a rather pitiful version with a long pull shifter that never seemed to run very well.
At left, a Rohloff hub.
Today, companies like Sunrace-Sturmey, Shimano, and Rohloff continue to develop internal gear hubs with more gearings, but they remain in the minority. The internal gear hub, as high-performance equipment is more or less done. But the internal gear hubs soldier on in utility bikes, commuters, and rental bikes.