25That is the position in the case of a two-year time-limit since, in principle, that enables any normally attentive taxable person validly to assert the rights derived from EU law (see, to that effect, Alstom Power Hydro, paragraphs 20 and 21). This is true also of a two-year time-limit in respect of the right to a refund of VAT paid, but not due, to the tax authority.