Any intervention by Mr Flynn in the Amsterdam Treaty debate "must be absolutely objective, factual and impartial", according to Mr Anthony Coughlan, of the National Platform.
A failure by Mr Flynn to abide by this requirement could render the Amsterdam referendum result open to challenge and could "lay Commissioner Flynn and his fellow Commissioners open to an application for injunctive relief in the European Court of Justice".
Mr Coughlan's comments yesterday followed an Irish Times report that Mr Flynn has been threatened with legal action if he campaigned in favour of a Yes vote. The threat was made by solicitors for Mr Owen Bennett, a member of the National Platform, acting in an individual capacity.
Mr Coughlan said in a statement yesterday that the EU Commission had no role in the treaty ratification process under European law. This had been fully accepted by the Secretary General of the Commission, Mr Carlo Trojan, in a letter last February to Ms Patricia McKenna, which said: "The European Commission has no intention of interfering in any way with the Irish referendum process."
Therefore, any intervention by Mr Flynn must be "in no way open to the construction that it constitutes advocacy, whether explicit or implicit, such as might influence the Irish people to vote one way or another in the May 22nd referendum".
Mr Bennett said yesterday he was not challenging Mr Flynn's right to free speech, as Mr Flynn had insinuated. His objection was to a member of the Commission having any involvement in the campaign.