This is a good article with good advice but I think it creates some unnecessary doubt on HMRC's position with regard to storing electronic records and discarding the paper originals. HMRC's position has been stated as:

“Records may be preserved on optical imaging systems, and the originals discarded, provided that what is retained in digital form represents a complete and unaltered image of the underlying paper document.”

This means that scanned documents, or indeed documents produced electronically (such as pdf invoices) are sufficient. For more information:

Good post Rachael, but also thanks to Michael for assisting with the clarity on paperless systems. I am on a paperless quest and am constantly asked by clients for confirmation that a receipt can be binned after being scanned.

You only need to search this website, which I won't redact, for all the comments about the problems with digital copying of invoices to know that such is not perfect. For the vast majority of businesses they should keep the actual paper document as actual evidence.