Boring a 125ci AF motor to a 200ci A motor

[montanafordman]

Not meaning to skew the conversation, but why did Europe use smaller blocks / bore size? Was this all European countries or a select few? Was it because of a perceived safety issue, governments wanting to legislate or tax based on emission or fuel mileage, etc.? I saw the note about them in the recent restorer but it didn't seem to give a clear reason.