24The Court has already held that national measures which bring about, de facto, a system of strict joint and several liability go beyond what is necessary to preserve the public exchequer’s rights (see Federation of Technological Industries and Others, paragraph 32). Imposing responsibility for paying VAT on a person other than the person liable to pay that tax, even where that person is an authorised tax warehouse-keeper bound by the specific obligations referred to in Directive 92/12, without allowing him to escape liability by providing proof that he had nothing whatsoever to do with the acts of the person liable to pay the tax must, therefore, be considered contrary to the principle of proportionality. It would clearly be disproportionate to hold that person unconditionally liable for the shortfall in tax caused by acts of a third party over which he has no influence whatsoever (see, to that effect, Netto Supermarkt, paragraph 23).