I am in a windowless basement in central London with two men I've only just met. It sounds like this story could veer toward the salacious, but bear with me.
The men boot up computers and switch on an electrical capacitor, which makes a low hum. I am asked if I have ever had any heart problems or epilepsy, or if I am on medication. No, no and no. "OK then," one of the men says, "here we go."
He picks up a plastic-covered rod that looks like something you might beat a carpet with, smaller than a tennis racket, with a figure-8 shape on the end and a cable attached to the handle. He places the wand on the crown of my head and tells the other man, "Energize."