Well on the one hand you're saying it's not that strange, on the other there's the election process for who can become Lord Mayor of the City of London. ;)

In most parts of the country the "Worshipful Society of Apothecaries" plays very little part in local governance...

Here's another video from CGP Grey that explains it rather well:-

https://www.youtube.com/watch?v=z1ROpIKZe-c

...and when did all this start? No body knows. It's so old there are no records.