What electoral event occurs when a Member of Parliament (MP) either dies or resigns from their position?

Okay, so when an MP can no longer serve, whether it's due to death or resignation, we need a way to fill that vacant seat in Parliament without waiting for the next scheduled General Election. That's where a by-election comes in. Think of it as a mini-election, but only for that specific constituency that the MP represented. It's important because each constituency needs representation in Parliament to ensure all voices are heard. The UK electoral system is based on constituencies electing individual MPs to represent them. If someone just "took over," that wouldn't be democratic, as the people of that constituency wouldn't have a say. And while a General Election involves the whole country voting for all MPs, it would be impractical and unnecessary to hold one just because one MP has left their post. A by-election ensures that the constituency continues to have a voice in Parliament in a timely and democratic manner.