Mr Matthews is known for writing books on paranormal subjects, including ghost sightings, UFOs, and cryptozoology (a pseudoscience focused on legendary animals, such as Bigfoot).
During the announcement of his defection, Mr Matthews criticised the criminal justice system, blaming “wokeness” and accusing politicians of adopting policies from “failed states”.
Reform UK also announced that Vanessa Frake-Harris MBE, a retired governor of Wormwood Scrubs, has joined the party.
Ms Frake-Harris, who will contribute to Reform UK's law and order taskforce, criticised successive governments for the current “crisis” in the prison service.