Armor production limits an early King George V program

How quickly could Britain complete the King George V class if construction began in 1931?

With an expensive early industrial push, the ships might enter service around 1935-36, but armor-plate capacity would be the dominant bottleneck.

The answer points to Admiral Henderson's later investment in armor facilities as work that would have to move forward with the ships. Hulls and other machinery were within reach, but producing sufficient high-grade armor steel at the required scale was slower and more expensive. Starting earlier therefore shifts industrial spending rather than simply shifting a laying-down date.