Both auction houses held separate surrealist sales that brought strong prices for artists including Rene Magritte and Joan Miro.
At Sotheby's, "The Farmer and his Wife," a vivid Miro canvas from 1936 once owned by filmmaker Billy Wilder, sold for just under 5.9 million pounds ($9.3 million).
Salvador Dali's 1943 "Portrait of Mrs. Harrison Williams" — an image of a famous New York socialite who later became Countess Mona Bismarck — sold for just under 2.3 million pounds ($3.6 million).
Works by Egon Schiele and Claude Monet also commanded high prices at the week's auctions, although some high-profile lots failed to meet their reserve prices.
Three works by Schiele raised a higher-than-expected total of 14 million pounds ($22 million) at Sotheby's, with one — "Lovers (Self-portrait With Wally)" — netting just under 7.9 million pounds ($12.4 million), an auction record for a work on paper by the early 20th century Viennese artist.
"There has been a lot of talk about the Impressionist and modern market dying out because of a lack of a material," Tully said. "But when really good property shows up there seems to be a lot of appetite for these works."
Jill Lawless can be reached at http://Twitter.com/JillLawless