In a debate that saw parties present entrenched positions, the SDS advocated the view that it made financial sense to hold both polls on the same day, which they said would also increase turnout and bolster the democratic legitimacy of the vote.

The coalition, meanwhile, variously insisted that the EU election should not be overshadowed by the archives debate, and that archives were too important a topic and needed to be subject to separate campaign.

The vote capped months of bitter bipartisan debate that was settled in the interim by the Constitutional Court, which ruled last week that the original referendum decree was unconstitutional in that holding the referendum on 4 May would put early voting in the midst of the May Day holiday and disenfranchise voters.

While the court held there were no obstacles to holding a referendum on the same day as an election, it did not specifically order the National Assembly to schedule the vote for 25 May, it only said a new referendum decree needed to be adopted within a week.