6) KSI

KSI is Britain's biggest YouTuber, and is also one of the top-earning content creators.

The 30-year-old social media star – whose real name is Olajide Olayinka Williams Olatunji - started his career by making video game let's-plays and skit videos, and quickly rose to popularity in the UK.

KSI also has a pop career and has collaborated with the likes of Anne-Marie, Craig David and Offset.

The YouTuber is also well-known for his boxing career, having gone toe-to-toe with fellow content creator Logan Paul and having a nearly perfect record, having only lost to Tommy Fury.

Currently, KSI's current estimated yearly earnings are $24 million, which is made up from his YouTube and music revenue, on top of the money he earns through his energy drink company Prime – which he owns with Logan Paul.