Legislation: EU law (Principal VAT Directive): Article 62 chargeable event and chargeability (general provisions)
For the purposes of this Directive:
(1) “chargeable event” shall mean the occurrence by virtue of which the legal conditions necessary for VAT to become chargeable are fulfilled;
(2) VAT shall become “chargeable” when the tax authority becomes entitled under the law, at a given moment, to claim the tax from the person liable to pay, even though the time of payment may be deferred.
Article 62 creates the concepts of chargeable event and tax becoming chargeable. A chargeable event arises when something occurs (a supply) that is subject to VAT. The time the tax becomes chargeable fixes the point at which the person, from whom the VAT is due, becomes liable to account for it to the tax authorities in the Member State concerned. However, the time of physical payment may be different - for example it may be linked to the later end of an accounting period.