The arrival of Declan Ganley on to the Irish political scene has unnerved and terrified the ruling elite in both Ireland and Europe. No one predicted it and no one could have foretold quite the impact it would have.

Last June, Ireland held a vote on the Lisbon Treaty, the latest legal document of the European Union to be put before the Irish people by way of a constitutional referendum.

Lisbon was, of course, the successor to the ill-fated Constitutional Treaty, shot down in flames by the voters of France and Holland. Rather than accept defeat, however, EU leaders dressed up the treaty in new clothes, calling it the Lisbon Treaty and then conning their electorates into thinking that it wasn't really the same thing at all and therefore didn't need to be put before them again.

Ireland was always going to be a potential fly in this particular ointment. Thanks to the Irish Constitution - a wonderful document - any ceding of sovereignty from the nation-state to a supranational body like the EU has first to be approved by the people.

Thus was the scene set for the Lisbon Treaty vote of last summer. It was one the political establishment was almost sure to win, especially after Bertie Ahern, damaged by revelations about his personal finances, had been replaced as Taoiseach by Brian Cowen, his gruff Finance Minister.

They did not reckon on Declan Ganley entering the fray. No one did. His entry, and subsequent success, provides an object lesson in how someone with no apparent political base, no grassroots organisation and a message still in gestation, but who happens to be in the right place at the right time, can defeat a deeply entrenched political establishment.