Gangland hard man Derek ‘Bottler’ Devoy claimed that a breakdown followed the guilt he felt at the murder of his sister Antoinnette and led him to a lethal grapple with police while he was armed with a submachine gun and a grenade.

But now, the volatile criminal has become a peacemaking king of his wing in Portlaoise prison where a piece of leaked mobile phone footage has shown him intervening in a row.

Crime World, with Nicola Tallant, is a weekly Iri…