Labour Party Senator Joe Costello today lost his High Court bid to stop An Post from continuing to frank mail with a Fianna Fáil (FF) election slogan.
But Mr Justice Philip O'Sullivan ordered An Post to provide the Senator - who is standing for election in the Dublin Central Dail constituency - with a franking machine so none of his outgoing mail will bear the FF slogan.
Since March 1st and until May 31st, most mail in the Republic bears an advertising stamp with the words: "Fianna Fáil, The Republican Party - A Lot Done - More to Do".
This followed a decision by the party to enter into a contract with An Post for the use of its Post Mark Advertising Service - a service that An Post says was available to all political parties.
During the two day challenge by the Senator, An Post said the Senator could, if he wished to avoid the slogan appearing on his mail, avail of a franking machine since franked letters did not carry any post mark advertising.
The Senator had sought a Court injunction to restrain An Post from attaching any political slogan to postal packets sent by members of the public through the mail.
His bid to stop this form of mail advertising was opposed by An Post, which was joined by Fianna Fáil as a notice party in the proceedings.