The British approach is you need evidence the recipient is not receiving your supply "for a wholly private purpose." VAT registration numbers are considered the

The British approach is you need evidence the recipient is not receiving your supply "for a wholly private purpose." VAT registration numbers are considered the best evidence, but alternative evidence can be accepted, such as a contract, commercial documents, a purchase order, etc. Whatever evidence you have, you need to keep and be able to defend. HMRC (the UK tax authorities) even say "a digital certificate from a reputable organisation can also be used" but that sounds like a logistical headache. As with most things tax related in the UK, it comes down to whether you think you're within the rules as best you interpret them, and whether you're confident you can honestly defend your stance to a VAT inspector. Other countries may not operate similarly, but the UK tax system tends to operate via debates over intents and outcomes rather than strict adherence to statutes. More information on the above at http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageLibrary_ShowContent&propertyType=document&id=HMCE_PROD1_029955#P1106_138630 http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPort...