Where must you be registered to exercise your right to vote?

To participate in UK elections, you need to be on the electoral register. Think of it like this: the electoral register is the official list of everyone who's eligible to vote in a particular area. It's how the government knows who you are, where you live, and that you're qualified to vote. Registering is a straightforward process, usually done online, and it's essential for exercising your democratic right. Without being on the register, you won't receive a polling card, and you won't be able to cast your vote. Other options like the "UK Registry" or "UK Database" don't exist in the context of voting, and the Home Office deals with immigration and security, not voter registration. So, being on the electoral register is the key to having your voice heard in UK elections.