One of Hannan's longest-running campaigns as an MEP was for a referendum – first on the European Constitution and then, when that text was revised and renamed, on the Lisbon Treaty. He would end every speech, whatever its subject, with a call, in Latin, for the Lisbon treaty to be put to the vote: ""Pactio Olisipiensis censenda est"". The words were a deliberate echo of Cato the Elder, the Roman Senator who ended every speech with a call for Carthage to be destroyed: ""Carthago delenda est"".- </ref>