After announcing last week that he had left the Socialist Party, Paul Murphy has today launched a new political party called RISE.
Murphy came to prominence for his role in the anti-water charge protests, which helped him win the Dublin South-West by-election in 2014.
He is one of the key figures featured in a new book about the water protests, In Deep Water: How People, Politics and Protests Sank Irish Water, written by Sunday Business Post political editor Michael Brennan.
Michael joined us to talk about the book and how the issue divided the country.
Listen to the interview in full by pressing the play button on this page.