Legislation: EU law (Principal VAT Directive): Article 63 chargeable event
The chargeable event shall occur and VAT shall become chargeable when the goods or the services are supplied.
The chargeable event occurs when the goods or services are supplied. This is also the starting point in terms of when the tax becomes chargeable. Although UK VAT law does not exactly mirror the EU concepts of chargeable event and chargeability our basic tax point is the equivalent of the chargeable event.