UK police say gambling over the Internet is becoming a cause for concern with investigations being launched into virtual casinos.

The Association of Chief Police Officers' Computer Crime Group says there is no guarantee that online games such as roulette are played fairly and gamblers giving their credit card details could be putting themselves at financial risk.

There are now more than 200 gambling-related Websites on the Internet and numbers are doubling every year.

In the US, the Senate voted to ban online gambling last July. But the European Commission has only got to the stage of studying the issue.

Online but offshore

The problem is that most virtual casinos are based offshore making them difficult to regulate. Such casinos, where roulette, blackjack and other games can be played on-screen, are illegal in the UK.

But the UK's Gaming Board is concerned that organised crime can still exploit online gambling because the Internet can cross any border.

The charity Gamcare, which promotes responsible gambling, is worried about increased accessibility. Betting is moving from High Street bookmakers to be available in the office or a teenager's bedroom, increasing the temptation to gamble.

For police, crime is a greater concern than addiction. How do you know a computer game of roulette has not been fixed and can you trust giving your credit card details to an organisation based on a small offshore island?

Big profits, little regulation

The online gaming industry could be worth $25bn by 2000 yet adequate regulation is still not in place.

In the US, one woman who sunk into debt by $70,000 through online gambling is taking advantage of its illegality.

Cynthia Haines is countersuing Internet betting companies and Visa and Mastercard saying that transactions between them were unlawful so payment of her debts is unenforceable.