Professional poker player under scrutiny after extraordinary run of success at game of chance

Phil Ivey has career winnings of £9m as a professional poker player (AFP)

Britain's oldest casino has refused to pay out £7.3m to a world-beating poker star and has launched a probe into how he took on the house at a skill-free game of chance, and won.

Crockfords, an exclusive gambling club in Mayfair, London, is witholding the winnings accrued by the professional Las Vegas poker player, Phil Ivey, at a private game of Punto Banco in August.

Mr Ivey, 35, was playing with a female companion when he started to enjoy a winning streak at the card game, in which players aim to hold cards with a combined value of nine or closest to nine.

Mr Ivey bet up to £150,000 a hand while playing in a private room at the Curzon Street casino on 25 and 26 August. The North American variant of baccarat, Punto Banco is favoured by so-called "high-rollers" as it offers marginally better odds than roulette.

Crockfords has informed the Gambling Commission that it is withholding Mr Ivey's winnings. The commission said it could not comment on specific details of the case, but a spokeswoman added: "Licensed operators are required to have a clear policy on dealing with complaints, including disputes."

Crockfords was founded in 1828 and is the oldest casino in Britain, but is now owned by the Malaysian gaming corporation Genting. It had initially agreed to transfer the winnings to Mr Ivey's bank account, but so far has returned only his original £1m stake.

Investigators from Genting have flown to London from Kuala Lumpur to interview staff – including a croupier working on the nights Mr Ivey played – and to review surveillance videos and examine the cards used.

Mr Ivey, who is often referred to as the "Tiger Woods of poker", is thought to be the world's sixth-highest earner from tournaments, amassing winnings of $14.6m (£9m). He was unavailable for comment yesterday.

Crockfords would not comment, citing the "confidentiality of the relationship between ourselves and our client".

Mr Ivey is thought to have initially incurred losses of almost £500,000 before he recovered, ended the first night £2.3m ahead. That total rose to £7.3m by the end of the second night.

A former manager at some of the leading London gaming clubs commented yesterday: "These casinos are used to big players and it is not unusual for £12m to £15m to change hands. There could be any number of things the casino might suspect, but they do not stop payment without a valid reason."

Punto Banco: how to play

Punto Banco is usually played by groups of up to eight players who wager that either the player ("Punto") or banker ("Banco") will win the hand, placing their bets on the appropriate area of the gaming table accordingly. Its appeal rests on pure luck as each new card is drawn by the croupier from a shoe containing four, six, or eight decks of cards. Each card drawn can radically alter the dynamics of the game, as in blackjack. The aim is to hold cards with a count of nine or closest to nine. Unlike its sister games chemin de fer and baccarat, as played by James Bond, there is no element of choice or skill.