It is a seat of parliament for the Clacton constituency (https://en.wikipedia.org/wiki/Clacton_(constituency)). If you're American, think of it as a Congressional District, and it's a special election.

Basically Nigel Farage won the seat to become a member of parliament representing the Clacton district. Then, there was an ethics scandal, so Nigel Farage resigned his seat, but is running in the special election to fill the vacancy. All the other serious political parties (Greens, Labour, Conservatives, Restore) think this is a stunt and a waste of time, so they aren't running any candidates. So, Nigel Farage is the only "real" politician in the race, and the "silly" candidate with the most support is Count Binface. So the special election ends up being between Farage and Count Binface.

Thank you!