Had not heard about this guy before, but he's quite a character. He's been excommunicated from the Catholic Church for some 20 years, and yes, the old adage that if you scratch a Truther, you'll find a Holocaust Denier underneath applies:
A senior bishop of the Lefebvrist Society of St Pius X (SSPX) has endorsed the Protocols of the Elders of Zion, a notorious anti-Semitic forgery that enjoys widespread currency in neo-Nazi circles.
Richard Williamson, one of four bishops ordained by Archbishop Marcel Lefebvre, told The Catholic Herald that the document - which supposedly reveals a Jewish plot to dominate the world - was authentic.
I like this description of him:
Dr Shimon Samuels, the centre's director of international relations, described Williamson as "the Borat of the schismatic Catholic far-Right" and said that he was "a clown, but a dangerous clown".