Quoting Luke <..hidden..>:
From the web site:http://www.hmrc.gov.uk/vat/records-valid-invoice.htm We get this: " How VAT sales invoices must be numbered You must number your sales invoices in sequential order. If you spoil or cancel a serially numbered invoice, you must keep it to show to a VAT officer at your next VAT inspection. "
Thanks. Thus spake the taxman, and forthwith appeared a greyish throng of auditors who wailed and thus addressed their mournful song: "Audit your accounting 'cos the taxman you can't fleece, and numbers on the invoices begin and never cease." (With apologies to Nahum Tate) R