A half-smoked cigar abandoned by former British prime minister Winston Churchill has sold for more than $7,000.

The cigar was tossed aside by Mr Churchill as he headed to an urgent meeting of his cabinet in 1941, the auction house Keys said.

The 10-centimetre stump was saved by a servant at 10 Downing Street and later given to a friend as a gift. A relative took possession of it after the man died.

Like many of the cigars he smoked at the time, this one bore a personalized label, which continues to adorn the stick.

Churchill, a passionate cigar smoker, served two terms as prime minister between 1940 and 1955.