Thomas Mair "betrayed the quintessence of our country" in the senseless killing of MP Jo Cox, the judge said as he sentenced him to a whole life term in jail.
Mair, 53, shot and stabbed the 41-year-old mother-of-two in the street in Birstall, West Yorkshire, as she arrived at the village library to hold her constituency surgery.
Witnesses testified that Mair had shouted "This is for Britain" or “keep Britain independent” as he carried out the murder.
Mr Justice Wilkie dismissed Mair's assertion of being a patriot, saying: "You affect to be a patriot. The words you uttered repeatedly when you killed her give lip service to that concept. Those sentiments can be legitimate and can have resonance but in your mouth, allied to your actions, they are tainted and made toxic.
"It is clear from your internet and other researches that your inspiration is not love of country or your fellow citizens, it is an admiration for Nazism, and similar anti democratic white supremacist creeds where democracy and political persuasion are supplanted by violence towards and intimidation of opponents and those who, in whatever ways, are thought to be different and, for that reason, open to persecution."
Justice Wilkie said Jo Cox was "a credit to herself, her community, and her country" and "In the true meaning of the word she was a patriot."
Justice Wilkie told Mair: "You are no patriot. By your actions you have betrayed the quintessence of our country, its adherence to parliamentary democracy. You have not even had the courage to admit and acknowledge what you did."
He said by forcing the prosecution to "prove the case in detail", added "deliberately" to the anguish of Jo Cox's family and forced the witnesses to relive the events.