In that thick square book, whose pages are of granite and whose bindings are of brass, titled The True Believer’s Bible, or Ten Thousand Rules for Swallowing Rubbish Whole, there is an article of faith that runs: “If a man of science supports your claim, it must be true.” Thus, flying saucers must be real because some Americans with PhDs think so, and crop circles must be made by aliens, despite the repeated admissions of large numbers of male humans who, stoically facing middle age, can think of no better ways to meet girls and while away their weekends.

For those who regard spiritualistic mediums as providing evidence, or even proof, of life after death, one medium is unanimously acclaimed as the greatest exponent of her craft: Florence Cook, who between 1872 and 1874 regularly produced the fully materialised spirit of Anne Owen Morgan, better known as ‘Katie King’.