Aimed at keeping witches out of the house, it was found during the restoration of a door at Coldweather House, off Halifax Road, Nelson, which has a history dating back to at least 1246.
But Mr Clayton, who wrote the book The Lancashire Witch Conspiracy, has carried out extensive research to establish the date of the witch charm – and he believes it is little more than 200 years old.
He said: “In 2001, Mr John Tattersall, the occupier of Coldweather House, discovered a document while renovating the main door of the property. The paper was folded and secured by means of a red wax, unimpressed seal.”
Mr Tattersall told Mr Clayton about it this month. Researching the paper and ink used, he believes it is not too old, although it is similar in style to some extent to others found in Foulridge, Rossendale and Ribble Valley.
He has looked at the Robertshaw family, who lived at Coldweather. John Robertshaw and his son Ambrose died within a year of each other and Mr Clayton said: “Were both John and Ambrose suffering from some affliction?
“If so, it is not difficult to imagine John would have resorted to any possible means of protection – in other words, the charm could be seen as a type of insurance policy!”
Mr Clayton believes the witch charm dates from 1750 to 1825 and was possibly introduced by John’s son, John junior. He said: “We will never know the exact reason why John thought he needed the charm or exorcism.
“The document might have been an impulse purchase from a door-to-door traveller as a good-luck token for his new house, or his actions could have been the consequence of some perceived threat.”
He added: “It is a unique example, and as such it is of importance to the cultural history of the local area and the national picture.”