A is unfolding in courts across Europe for control of the multi-billion-euro online gambling market, pitting gaming companies against governments anxious to safeguard revenues from national lotteries.

At stake is the European gamblers euro in a rapidly-growing market with turnover of over $100 billion per year. Experts say governments will not be able to protect their lotteries for long, and barriers to cross-border gambling will crumble under a growing wave of legal challenges.

Between 1992 and July 2004 the restrictions were challenged five times in European courts. But they have been challenged four more times in the last year alone.

"It's no longer a case of 'will' the barriers come down, but more a question of 'when'." said Belgian lawyer Ewout Keuleers.

Although European Union law allows cross-border trade by online gambling companies, many individual states prevent it, claiming they are protecting the public from a gambling addiction. However, critics note these same states run equally addictive national lotteries and accuse them of hypocrisy.