Complex sentence: He stood successfully for the UK Independence Party (UKIP) in the 2004 election to the European Parliament, before leaving them in 2005 to found a new party called Veritas, from which he in turn resigned as leader later the same year.
Split into simpler sentences: He stood successfully for the UK Independence Party (UKIP) in the 2004 election to the European Parliament. He left them in 2005 to found a new party which he called Veritas; he resigned as its leader later the same year.