No — a clear digital image is an acceptable record, and you can throw the paper away once it is captured, with one significant exception. HMRC accepts scanned or photographed documents provided the image is legible and shows all the information the original did. The exception is anything showing VAT paid that you intend to reclaim on an unusual footing, and any document you might need in original form for a non-tax reason, such as a warranty or a legal dispute. The practical failure mode is not legality but legibility: a blurred, half-cropped photo of a faded till receipt is not a record, it is a picture of one. Most software has a phone app that captures, reads and files the receipt against the bank transaction in one step.