MUST READ: Winston Churchill memorabilia sold at London auction

The Associated Press

LONDON -- Christie's said Tuesday it was auctioning what it said was the most important private collection of letters and books related to Britain's World War II prime minister, Winston Churchill.

The collection -- which included diary entries, letters, photographs and an unsmoked cigar -- was amassed over 30 years by Forbes Inc. chief executive Steve Forbes, the auction house said. It was expected to raise at least $1.5 million.

One of the items was Churchill's engagement diary, which Christie's said is the most important surviving source for his daily activities.

The diary was kept by the leader's private secretaries and recorded the Churchill's appointments from 1939 to 1945, including summits with Josef Stalin and Franklin D. Roosevelt. It is valued at between $120,000 and $180,000.

Other highlights included a first edition of Churchill's book ''Arms and the Covenant'' that the leader gave to Guy Burgess, the infamous double agent who spied for Britain during the war but was later revealed to have been recruited by the Soviets.

The collection will be sold in three parts, in London and New York. The first part is due to go under the hammer in London on June 2.