The oldest and best-known saying in poker is: if you’re sitting at a card table and you don’t know who the mug is, then it’s you. In its cruel sagacity and alarming applicability, it’s a lesson that perfectly exemplifies why poker is now the hottest and hippest game in Britain.

As much as poker is redolent of a certain outlaw romance and cowboy mythology — it is the art of the nonconformist and inveterate outsider, the game of the grifter and the American pioneer, the honeypot to which every easy-money hipster and ruthless individualist seems inextricably drawn — its primary appeal lies in its unerring ability to act as The Great Educator.

Unlike bridge, which is played too readily for the society, and chess, which is too much for the mind alone, poker is a powerful test of temperament and character. It is, for those who have the “intestinal fortitude” and the ability to pay the fees, a game that can instruct you subtly in the ways and dispositions of your friends and enemies. Ultimately, of course, it can teach you about yourself.

That is why nine of the best poker players in the world will gather in a card room in Dublin tomorrow to compete for a pot of almost £450,000. While the winner of the game, the final of a week-long knockout tournament billed as the World Poker Championship, will walk away with a cool £175,000, something even more significant will be asserted. If money, as devotees say, is the language of poker, then this particular champion will be saying something pretty authoritative about the state of the game, the ability of his competitors, and about his place in the world.

While the World Poker Championship is unusual in that it has attracted the most intimidating hustlers, flashiest professionals and biggest money-winners from both the US and Europe — including the American Greg Raymer, who won a staggering $5 million last month at the game’s richest tournament, the World Series of Poker in Las Vegas — it is typical of the buzz of big money and edgy excitement that currently surrounds poker.

In fact, poker has never been so talked about and visible. Long associated with cowboys, outlaws, cheats and chancers, the toughest game in town has gradually moved away from the saloon and the speakeasy and on to television, the internet, glossy magazines, radio programmes, and the card tables of new, well- appointed city casinos throughout Europe.

In turn, its audience has exploded. A recent ICM poll for the bookmakers Ladbrokes suggests that a quarter of all British adults have played poker, and Channel 4’s pioneering series, Late Night Poker, broadcast after midnight, has attracted an audience of 1.3 million.

With the amount being gambled daily on the poker websites worldwide having grown last year from £6 million to £38 million, more and more companies are also realising that poker is good business. The Dublin tournament is being sponsored by internet casino and poker room The Gaming Club, and will be broadcast as a ten-part series on Sky Sports later in the year. Other networks such as ESPN, Discovery and Challenge have increased viewing figures and revenue by broadcasting poker events.

The game even has celebrity endorsement. This week the Hollywood star Ben Affleck won $356,400 (£196,000) at a poker tournament in California. An assortment of players as diverse as Martin Amis, Ricky Gervais, Sir Clive Sinclair, Stephen Fry, Tom Parker Bowles, the snooker players Stephen Hendry and Jimmy White, and Affleck and fellow star Matt Damon, has appeared on television playing poker. Damon starred in the Hollywood high-stakes poker film Rounders. In short, poker has gone mainstream.

Still, the game’s newfound accessibility on television and the internet only partly explain its growing popularity. Although women are playing the game in greater numbers and winning major tournaments, poker, for one thing, has also always stood as the acme of roguish machismo and the avatar of male mettle and nerve. Think of such films as The Cincinnati Kid and David Mamet’s House of Games, as well as such legendary players as Wild Bill Hickok, Damon Runyon and President Nixon.

“Poker has always had a pretty cool image,” Martin Amis says. “Whenever you see it on film, and even in novels, it is played by people who are very self-contained and are able to conceal their emotions, and these are qualities we very much seem to admire.”

Poker is about skill, chance and calculation. You have to know the odds and make them work in your favour; you must know which hands to bet everything on and which ones to walk away from; and you need to perfect the intricacies of poker’s greatest gift, the bluff.

Yet, poker is also about self-discipline, patience, humility, courage and inscrutability. It can teach you that it’s not just losing that can leave, as Anthony Holden has observed, “a deep spiritual bruise”, but that winning can be equally unsettling — and infinitely lonelier. It can prove, yet again, that pride comes before a fall. It is not for nothing that the collective noun for a group of poker players is a “school”.