LONDON (AFP) - A professional US poker player on Wednesday lost his case against a London casino that accused him of sneaky tactics after he won £7.7 million (S$15.8 million).

Crockfords Casino said the player, Phil Ivey, used a technique known as "edge-sorting" in a game of baccarat to work out which cards are which by how the patterns are printed on their backs.

The High Court in London ruled in favour of the casino in the upmarket city centre district of Mayfair, where Ivey played in four sessions over two days in August 2012.

"We attach the greatest importance to our exemplary reputation for fair, honest and professional conduct," a spokesman for Crockfords said after the ruling.

A spokesman for Ivey quoted him as saying: "I believe that what we did was a legitimate strategy.

"We did nothing more than exploit Crockfords' failures to take proper steps to protect themselves against a player of my ability," he said.

The casino sent back the player's stake money of £1.0 million but not the winnings.