It all goes back to the days of Guy Fawkes and King James I (James VI of Scotland) After the Stuarts came to the throne, they brought back Catholicism after the Tudors had changed the religion to Protestant with the C of E. Guy Fawkes I think was the one who led the revolution against the King (correct me if I'm wrong), and stormed the Houses of Parliament with the gunpowder plot. Hence Nov 5 being celebrated as Guy Fawkes Day.
So yeah, I guess it is anti-Catholic. He might have had more success in N Ireland had he been there.