An instrument is false for the purposes of this Part of this Act—
if it purports to have been made in the form in which it is made by a person who did not in fact make it in that form; or
if it purports to have been made in the form in which it is made on the authority of a person who did not in fact authorise its making in that form; or
if it purports to have been made in the terms in which it is made by a person who did not in fact make it in those terms; or
if it purports to have been made in the terms in which it is made on the authority of a person who did not in fact authorise its making in those terms; or
if it purports to have been altered in any respect by a person who did not in fact alter it in that respect; or
if it purports to have been altered in any respect on the authority of a person who did not in fact authorise the alteration in that respect; or
if it purports to have been made or altered on a date on which, or at a place at which, or otherwise in circumstances in which, it was not in fact made or altered; or
if it purports to have been made or altered by an existing person but he did not in fact exist.
A person is to be treated for the purposes of this Part of this Act as making a false instrument if he alters an instrument so as to make it false in any respect (whether or not it is false in some other respect apart from that alteration).