The Supreme Court referred an appeal by convicted murderer Graham Dwyer to the European court last year over questions about the Communications (Retention of Data) Act 2011 and its compatibility with EU law.

Judge Eugene Regan was among the judges who presided over a hearing on Monday, but has now recused himself after The Irish Times pointed out he had spoken in favour of the law during a Seanad debate in 2011.

Judge Regan was a Fine Gael senator from 2007 to 2011 and the party’s Seanad spokesperson on justice, equality and law reform.

A spokesperson for the European Court of Justice told The Irish Times: “Until it was brought to his attention this week by your query, Judge Regan had no recollection of his involvement in the passage of the Communications (Retention of Data) Act 10 years ago.

“However, to avoid any doubt as to his independence, Judge Regan has informed the president, pursuant to article 18 of the statute of the court, that he is recusing himself from this case with immediate effect.”

The judge added that there was “no harm done” as deliberations in the case had not yet begun.