Which groups of adults are generally eligible to vote in all UK elections?

Okay, let's break down who gets to vote in UK elections. The right to vote, or suffrage, has expanded over time in the UK. Initially, it was tied to property ownership and gender, excluding many. Now, the core principle is that adult citizens of the UK, whether born here or naturalised, have the right to vote. Naturalisation is the process where someone from another country becomes a British citizen. But it doesn't stop there. Reflecting the UK's historical ties, citizens of the Commonwealth who are resident in the UK are also eligible to vote. The Commonwealth is a group of countries, mostly former British colonies, that maintain close links with the UK. So, the key is citizenship, either UK citizenship or citizenship of a Commonwealth country combined with residency in the UK. That’s why focusing only on UK-born citizens is too narrow, and including US citizens is incorrect, as citizenship of the UK or a Commonwealth country is the key requirement.