The addictive fantasy game, which allows an unlimited number of players to compete over the internet, is introduced in Britain this weekend.

More than 100,000 copies have already been ordered, adding to the 700,000 sales in North America, Australasia and Asia since its Christmas release.

It sounds like a 3-D Dungeons & Dragons, but the game, costing £30, has a devilish way of extracting more money from its obsessive players. There is a monthly subscription fee of £8, otherwise, competitors are ejected from their fantasy kingdom. At peak hours 250,000 people were playing simultaneously in the US, Australia and New Zealand, with a further 100,000 battling away in South Korea.

In the US there are already reports of jaded office workers recovering from 18-hour sessions driving dwarfs from the windswept plains of the Arathi Highlands. The computer game bill has joined the mobile phone and broadband access as a direct debit in thousands of households.

It was created at Blizzard Entertainment, an American company that has sold 40 million games in the fast-rising genre called massively-multiplayer online role-playing games (MMORPG). The Matrix trilogy is being turned into a MMORPG, but some games have attracted controversy by asking players to spend real money in order to purchase virtual items which can be traded as part of the fantasy.

Last December, a player of Project Entropia paid its creators $26,500 (£14,100) for a 6,000-acre “treasure island” in the game’s virtual world.

The money could theoretically be recouped through “mining” rights and the sale of land plots. More than $100 million is spent each year trading items in online games. Blizzard has restricted its Warcraft cash-economy to a monthly subscription to avoid charges of player exploitation. The company can claim to have created a genuine online community through its game.

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