Political ideology
The Duke was described as "a pure Victorian who had eyes for his shotgun, his hunters, his dogs ... a man who enjoyed hiding diamonds under the pillow of his mistresses …" He was known for being very conservative and, later, right wing.
The Duke was notable for being opposed to homosexuality. In 1931, the Duke exposed his brother-in-law William Lygon, 7th Earl Beauchamp (1872–1938) as a homosexual to the King and Queen. He reportedly hoped to ruin the Liberal Party through Beauchamp. The King was horrified, supposedly saying, "I thought men like that shot themselves." Following Beauchamp's departure for the continent after the Duke had assembled sufficient evidence to incriminate him, forcing the Earl to resign his public offices, the Duke sent him a note which read, "Dear Bugger-in-law, you got what you deserved. Yours, Westminster."
During the run-up to the Second World War, he supported various right-wing and antisemitic causes, including the Right Club. His antisemitic rants were notorious.
In the summer of 1939, Westminster joined The Link as a member of its national council. The British historian Ian Kershaw wrote that Westminster "had a propensity to share some of the Nazis' delusions about Jews and Freemasons", which led him to join The Link. During the Danzig crisis, Westminster was said to have been especially concerned about the prospect of the German strategical bombing of London because he owned so much of central London. Along with Lord Mount Temple, Lord Brocket, the Duke of Buccleuch, Lord Mottistone, Lord Arnold, Lord Sempill and Lord Tavistock, the Duke lobbied the Chamberlain government to settle the Danzig crisis peacefully, preferably by Britain abandoning the commitment to defend Poland. The British historian Richard Griffiths described Westminster as being both "strongly pro-Nazi and anti-Semitic". Griffiths described him as a member of a "hard core" pro-Nazi faction in the House of Lords, who continued to defend Nazi Germany in the summer of 1939, even as the Danzig crisis pushed Britain closer to war. The main theme of the speeches of Westminster along with other pro-Nazi peers such as Lord Redesdale, Lord Brocket, the Duke of Buccleuch, Lord Mottistone, and Lord Sempill, was that Britain had no business being involved in the Danzig crisis and should withdraw from the crisis to allow Germany to settle its dispute with Poland in whatever manner it wished to do. In contrast to the unelected House of Lords, there were few MPs in the House of Commons who defended Germany in the summer of 1939, owing to the increasing unpopularity of Nazi Germany. Even pro-German MPs realised expressing such views might cost them their seats in the next general election. Griffiths described the pro-Nazi MPs during the Danzig crisis such as Archibald Ramsay and Cyril Culverwell as "eccentrics".
In her book The Light of Common Day, Lady Diana Cooper reminisced back to 1 September 1939. She and her husband, the prominent Conservative Duff Cooper, were lunching at London's Savoy Grill with the Duke of Westminster. She recalled:
When he [the Duke of Westminster] added that Hitler knew after all that we were his best friends, he set off the powder-magazine. "I hope", Duff spat, "that by tomorrow he will know that we are his most implacable and remorseless enemies". Next day "Bendor", telephoning to a friend, said that if there was a war it would be entirely due to the Jews and Duff Cooper.
Britain declared war on Nazi Germany on 3 September 1939, two days after the German invasion of Poland. Later that month, Westminster hosted two meetings at his house with various pro-Nazi peers and MPs. In this meeting, they discussed a way to make a negotiated peace with Germany. The Foreign Secretary, Lord Halifax, heard reports that the meetings at Westminster's house were "of a very defeatist character".
The Duke, known for his pro-German sympathies, was reportedly instrumental in influencing his former mistress, Coco Chanel, to use her association with Winston Churchill to attempt to broker a bilateral peace agreement between Britain and Germany. In late 1943 or early 1944, Chanel and her lover, German spy Hans Günther von Dincklage, undertook such an assignment. Codenamed "Operation Modellhut", it was an attempt involving the British embassy in Madrid and Chanel to influence Churchill, and thereby persuade the British government to negotiate a separate peace with Germany. This mission as planned ultimately met with failure, as Churchill had no interest.