Derek Francis Johnson, known professionally as Derek Acorah, was a British spiritual medium. He was best known for his television work on Most Haunted, broadcast on Living TV (2002–2010). His career as a medium was punctuated by allegations of fakery and he also attracted controversy over a number of seances during which he reportedly made contact with high-profile figures.

Most Haunted is a British paranormal reality television series. Following complaints, the broadcast regulator, Ofcom, ruled that it was an entertainment show, not a legitimate investigation into the paranormal, and "should not be taken seriously".