Upon asking about the Spanish equivalences of Senior, Junior and III, I got to know that these are commonly used in United States, but not that much in Britain. Talking about the United Kingdom, a user said:
(...) I suspect that since we do not have a common solution parents avoid the situation, We did have prime ministers called Pitt the elder and Pitt the younger but that is not a current usage as far as I know.
And in fact, Wikipedia on suffix names states that:
In the United States the most common name suffixes are senior and junior, which are written with a capital first letter ("Jr." and "Sr.") with or without an interceding comma. In Britain these are more rare, but when they are used the abbreviations are "Jnr" and "Snr", respectively.
So I wonder: how typical is to have the suffix name Senior, Junior or III in Britain? Is there a prevalence of it in any time in history?