The government has announced a crackdown on advertising by about 1,000 gambling websites operating from overseas.
Regulations being laid in Parliament on Thursday mean that when the Gambling Act 2005 comes into force on September 1, companies operating from outside the European Economic Area will be banned form advertising in the UK.
Sites such as William Hill Casino, Betfred Casino and Littlewoodscasino.com are all based in what are called "non-white listed jurisdictions", where regulations do not meet UK standards.
Culture secretary James Purnell said: "I make no apology for banning adverts for websites operating from places that don't meet our strict standards. Protection is my number one priority.
"The fact that only Alderney and the Isle of Man have been able to meet the high standards demanded by our white listing criteria shows how tough the Gambling Act is."
The Department for Culture, Media and Sport said Antigua is believed to have the largest number of gambling websites, followed by Costa Rica, Kahnawake - a Mohawk reservation in Canada - and the Netherlands Antilles.
Purnell rejected applications by the Netherlands Antilles to join the white list, while applications from Kahnawake and Antigua are still being considered.
Foreign countries have to demonstrate they have measures in place to protect children and vulnerable people, keep out crime, ensure gambling is fair, and prevent money-laundering.
The Gambling Act also brings with it a relaxation of the current rules surrounding advertising for all types of UK and EU-based gambling businesses.
Dods Parliamentary Communications Ltd