The lizard People theory was coined sometime in the 90s by David Icke. Icke once was a soccer player and host of a sports show on BBC but he went into far left politics. He was part of the Green Party. But in 1989-90 he has a vision and later read some books and he quit the Green Party. Today he is basically half conspiracist and half self-help guru. He is the Alex Jones of The UK. He tried a TV channel called The Free Speech Network in 2011 and went bankrupt. So he was on YouTube until they banned him for taking bad about China and exposing Covid-19.
David Icke and Alex Jones are in my opinion controlled opposition. Much like Pence and Ann Coulter