Christie's will offer for sale what the auctioneer called the most important private collection of papers related to British wartime leader Winston Churchill. The collection was assembled over 30 years by Malcolm S. Forbes Jr., a descendant of the Forbes magazine founder, and will be sold in three parts starting in London on June 2. The London sale is expected to fetch about 1 million pounds ($1.5 million). The sale will feature around 150 lots including letters, books, photographs and a cigar. Individual estimates range from 1,000 to 120,000 pounds ($182,800).