LONDON — London is poised to steal some of New York’s thunder in the booming international art market, with Christie’s and Sotheby’s set to sell as much as $600 million in evening sales here next week.

A strong pound against the dollar has added to what some observers say is a growing conception that London is gaining ground as a seller’s venue. The star work of Christie’s February 8 evening sale, Francis Bacon’s “Study for Portrait II,” hasn’t been publicly exhibited since 1963 and is estimated to sell for as much as $23.5 million, a record for the artist. The painting depicts a more subdued and stricken pope — his face half obscured in a pained meditation — than Bacon’s famous “screaming popes.”

“The ability to work with this piece of art is really one in a million,” the head of Christie’s Post-war and Contemporary Art Department in London, Pilar Ordovas, said.

As the art market accelerates and works are sold for record-breaking prices, more collectors are asking to be present in the room during the sale, she said.

“The market is so exciting at the moment,” Ms. Ordovas said. “It’s almost like going to the theater.” By the end of the year, all Christie’s auctions will be broadcast on the Internet through the company’s software program, Christie’s Live, a move that Ms. Ordovas said would allow anyone to watch the tense bidding in real time.

The Sotheby’s February 5 sale of Impressionist and Modern Art includes three works from the collection of the late Charles Lachman, a founder of Revlon cosmetics. An impressionist portrait by Pierre-August Renoir of two sisters reading a book, “Les Deux Soeurs,” is estimated to sell for between $11.8 million and $15.7 million.

Also included is a landscape by Maurice de Vlaminck estimated to sell for between $2.9 million and $4.9 million, and a painting by Raoul Dufy estimated to sell for $2.4 million and $3.5 million.

An Egon Schiele from 1911, “Prozession,” leads Christie’s February 6 evening sale of Impressionist and Modern art. The painting is estimated to sell for between $9.8 million and $13.7 million.

Sotheby’s February 7 evening sale of Contemporary art is leading with Gerhard Richter’s “Abstraktes Bild,” which is expected to bring in between $2.7 million and $3.5 million.

Both auction houses have billed the London evening sales as their largest European sales yet.

The director of Thomas Gibson Fine Arts in London, Hugh Gibson, said he sees no end to the sensational prices, whether in London or New York.

“There are these new hedge fund people, all who seem to have obscene amounts of money,” he said. “People have been saying the market is going to burst for years, but it goes on getting higher and higher.” There are also more Russian collectors in the market than there were in previous years, he said.

With demand for the best representative works of movements or artists increasing in a market with diminishing supplies, collectors have become more global in their approach to acquiring art.

Christie’s and Sotheby’s have responded by increasingly sending the signature works to cities in Europe and America a month before the sale for viewing. Major collectors may also request to privately see the work at their homes.

Still, where you sell art is an important factor, an art consultant, Peter Hastings Falk, said. American art tends to be sold where the market is strongest, which is New York, and likewise, European art tends to be sold in greater numbers in London.

As new collectors enter the market and factors such as the exchange rate come into play, specific markets can shift, he said.

“The buzz is that London is on the verge of displacing New York as the epicenter of the art world, but this really refers to contemporary art,” Mr. Falk said. “When we look at other market segments, such as Old Masters, traditionally ensconced in London, we see in the recent series of auctions the indication of a shifting of the traditional market center from London to New York. Certainly for Europeans buying in New York, the strength of the pound and euro are largely responsible.”