Under the Marrakesh Treaty, contracting states must make it legal for certain entities, including government institutions and non-profit organisations, to reproduce or distribute published work in a format accessible for the blind, visually impaired or those otherwise unable to read print.
The states must also promote cross-border exchange of these copies by allowing them to be exported or imported.
Several member states had argued that the European Commission did not have the exclusive competence to conclude the treaty, despite it having been requested to do so by the Council of Ministers in 2013.
However, the CJEU, Europe's highest court, said the Commission has the right to act on behalf of the member states, because the treaty affects an area governed by 'common EU rules', and the conclusion of the Treaty may "affect those rules or alter their scope".
"Since the conclusion of the Marrakesh Treaty may affect the directive on copyright or alter its scope, the Court concludes that the EU has exclusive competence and that the treaty may be concluded by the EU acting on its own, without the participation of the member states," it said.
Dan Pescod, head of campaigns at the Royal National Institute of Blind People (RNIB) said the
challenge to the Commission's competence to ratify the treaty has delayed progress by a year and a half, and "it is now time for the UK to back EU ratification without further delay".
The RNIB is concerned that the UK may still push for changes including a requirement that any book that is commercially available in an accessible format should not be covered under the treaty, Pescod said.
The German Copyright Act already includes similar permission to reproduce work for non-commercial purposes for disabled users, said technology law expert Igor Barabash, of Pinsent Masons, the law firm behind Out-Law.com. The German act includes a requirement for remuneration to be paid for the author, and the treaty appears to leave this decision open to individual countries, he said.
Copyright expert Iain Connor, also of Pinsent Masons, said: "This decision is a marker for Brexit. Should the Commission push ahead and ratify, then the UK government will have a decision to make as to whether, notwithstanding Brexit, it implements the change. A sticking point for the UK on measures such as these, which for example resulted in the UK scrapping its attempt to introduce a private copying exemption, is the fact that under UK copyright law there is no levy system which would provide a fund for fair compensation to be paid to rights holders."
"Accordingly, while the UK might wish to remain a good European until Brexit is achieved, a measure such as this might just be in the ‘too difficult’ pile," Connor said.