The diary of an anti-Semitic British socialite who was obsessed with Adolf Hitler and developed a personal relationship with the Nazi leader has been discovered, the Daily Mail reports.

The leather-bound diaries, lost to historians and not seen for eight years, appear to reveal the extent of the aristocratic Unity Mitford's relationship with the dictator.

Despite the infamous "Hitler Diaries" incident in which a Sunday Times reporter was tricked into publishing a fake report, some historians believe the discovery is genuine.

Speaking to the Daily Mail, which claims to have discovered the diaries, historian Lord Andrew Roberts said: "It is extremely rare in modern times for the diaries of a prominent figure in the Nazi movement to be discovered and published."

"I believe they are real," says historian and biographer David Pryce-Jones, one of the world's most renowned Unification Mitford scholars.

The salacious diaries detail how the socialite became obsessed with Hitler and stalked him when he moved to Munich at the age of 20. Handwritten diaries revealed that Unity - one of the famous Mitford sisters - was a Nazi admirer who shared Hitler's hatred. Jews.

Spanning 1935 to 1939, she documented "the best day of my life" in February 1935, when Hitler invited her to dine at the Osteria Bavaria restaurant.

She wrote: "Lunch at Osteria at 2.30. After I had finished lunch, the Führer came at 3.15. About 10 minutes later he sent Wirt (the boss) to invite me to his table.

"While he was having lunch, I went over and sat next to him and we talked. The best day of my life. He wrote me a postcard. After he left, Rosa (the waitress) told me that he used to be from No such person has been invited.”

Born in London, Mitford successfully integrated herself into Hitler's inner circle, so much so that her presence reportedly caused Hitler's lover Eva Braun to become jealous of their relationship.

The journals record a total of 139 meetings with the Nazi leader, whom she always referred to as "the Führer." She later described him as "very sweet and happy."

The last entry in her diary occurred on September 1, 1939, when Germany invaded Poland and declared war two days later. Unity, who was 25 at the time, later attempted suicide.

Apparently distraught at the prospect of Britain and Nazi Germany going to war with each other, she shot herself in Munich's Englischer Garten park.

The attempt was unsuccessful, but Unity suffered brain damage and the bullet remains lodged in her skull. She returned to England and died in 1948, aged 33.