[1] His book Catastrophe: An Investigation into the Origins of the Modern World (2000) on a 6th-century AD climatic disaster has had a mixed reception – he and his theory were featured in the 2000 Television pilot to the PBS series, Secrets of the Dead.
Key's work expands on that by Mike Baillie in Exodus to Arthur: catastrophic encounters with comets (1999) in which the primary evidence for the event is dendochronology (shown by narrow rings around c. 540 CE), as well as acidity in Greenlandic ice cores (suggesting volcanic activity), as well as accounts of historians such as John of Ephesus, Procopius, and Cassiodorus on changes in climate, including dimming of the sun.
The work has received mixed reviews: Publishers Weekly criticized the book, writing that "Huge claims call for big proof, yet Keys reassembles history to fit his thesis, relentlessly overworking its explanatory power in a manner reminiscent of Velikovsky's theory that a comet collided with the earth in 1500 B.C.
[5][6] Archaeologist Brian M. Fagan referred to it as "investigative journalism" and "an interesting and, at times, compelling narrative (and good television)" concluding that "Keys is right to draw attention to the importance of short-term climatic change, but, in our present state of knowledge, the deterministic and somewhat sensationally written Catastrophe goes too far.
In an Independent article published a few days after the coronation of Charles III and Camilla, he wrote: "In most examples of the abolition of monarchies in major countries, their demise was followed by a strengthening of the right and the erosion of democracy, justice, equality and liberty.