(1) If by law or otherwise a signature to a document is required to be witnessed (whether the requirement is in the form of an obligation or consequences flow from the signature not being witnessed) that requirement is taken to have been met if -

(a) the signature to be witnessed is an advanced electronic signature, based on a qualified certificate, of the person or public body by whom the document is required to be signed,

(b) the document contains an indication that the signature of that person or public body is required to be witnessed, and

(c) the signature of the person purporting to witness the signature to be witnessed is an advanced electronic signature, based on a qualified certificate.

(2) An advanced electronic signature based on a qualified certificate may be used as provided in subsection (1) only -