This article evaluates the EU stance on the unjust enrichment passing on defence. EU law requires the restitution of illegally collected tax. However, it permits Member States to deny restitution by arguing that the taxpayer passed on the tax to the end consumer and restitution would unjustly enrich him. This defence rests on frail grounds. For one, it is inherently difficult and excessively costly to calculate whether and to what extent there was passing on. Furthermore, it is ‘unjust’ to prefer the enrichment of the State that contravenes EU law at the expense of the law-abiding taxpayer. Thus, fully rejecting this defence makes sense. This would prevent both unnecessary legal uncertainty and injustices to the law-abiding taxpayer.
Capriles, Theo, Shortcomings of the EU passing on defence. World Journal of VAT/GST Law, Volume 1, Number 1, July 2012 , pp. 47-60(14).