[1] Treherne appears to have entered the forgery business about 1902 or slightly earlier when he was working as a clerk in Brighton.
Some of Treherene's best work is thought to be forgeries of the stamps of Jammu and Kashmir which he produced in whole sheets showing all of the varieties of type on the originals.
Kay wrote about forged stamps of Kashmir in Stanley Gibbons' Monthly Journal and in 1904 Charles Nissen wrote more generally in The Stamp Collectors' Annual about the wide variety of forgeries for sale in Brighton.
After a member received an order for a large number of Great Britain penny reds, the association set a trap for Treherne by marking some with a pin prick.
When the stamps were eventually sold, they had acquired a CYPRUS overprint not present originally, thus greatly increasing their value.