Churchill's cigar under hammer in London

A huge collection of diaries, letters and even a pristine cigar belonging to Winston Churchill, Britain's World War II prime minister, was up for auction in London Wednesday.

The sale, which is expected to raise around one million pounds (1.2 million euros, 1.5 million dollars), is being billed by auctioneers Christie's as part of the most important private Churchill collection in the world.

It features his engagement diary for 1939 to 1945 which records meetings with leaders including US President Franklin Roosevelt, Joseph Stalin of Russia and Britain's King George VI. It could fetch up to 120,000 pounds.

The Havana cigar - which along with the "V for victory" sign was Churchill's trademark - is unsmoked and dates from 1963, when it was given by Churchill to a fellow diner at the Hotel de Paris in Monte Carlo.

It is tipped to sell for up to 1,500 pounds.

"Winston Churchill is one of the most famous historical figures of the 20th century and his feats as a politician, and as the wartime prime minister of Great Britain in particular, continue to attract great attention and admiration," said Thomas Venning, Christie's London director of books and manuscripts.

"This outstanding collection presents an exceptional and fascinating insight into his personality, character, sharp wit and his distinctive way with words, with letters, photographs and books spanning his entire life".

The collection was amassed by US publisher Steve Forbes. Christie's is holding a second Churchill sale in New York in December and a third in 2011 in London.