A witness to an electronic signature can validly attest to it by adding
their signature, electronic or otherwise, when the party inserts their
electronic signature in the document. The current view of how this can
validly occur is that a witness must be physically present: they may not,
for example, use videoconferencing to remotely observe a party’s signature
being added to a deed.
It is likely that where there is a legal challenge to an electronic
signature on a document, it would be accepted by a court as authentic
unless evidence were given to the contrary. This is the same principle that
would apply to a wet-ink signature whose authenticity is challenged.
There are various cases where electronic signing may not be effective and
only a wet ink signature will suffice to make the document legally valid,
binding, and effective. For example, certain documents that are required to
be filed with the Land Registry need wet ink signatures, as do certain
documents where tax, stamp duty or cross border issues arise. There may
also be other exceptions.