Almost 60 people have been arrested worldwide as part of a long-running international undercover operation into the DarkMarket site led by the Federal Bureau of Investigation (FBI) in the
The closely guarded, invitation-only forum, inaccessible to most web users, allowed criminals to buy and sell stolen financial information, such as people's online banking details and credit card data.
It also gave the latest information on how to commit online fraud and what equipment to use in financial crimes.
Launched in 2005, the site, said by the authorities to be one of the most significant of its kind, had 2,500 registered members at its peak.
A SOCA spokeswoman said investigators infiltrated the forum in 2006 to gather evidence about the ringleaders.
"The thing with these sites is if you simply shut them down people transfer the activity elsewhere," she said.
"The idea is to take out the key, highly organized and sophisticated operators who set them up, monitor and run them."
Criminals could make "phenomenal sums of money" from their activities. One man linked to an earlier such site spent 250,000 pounds ($432,277) on stolen card data in six weeks.
"He could have, had he realized the full potential of those cards, made up to 10 million (pounds, $17.3 mln)," the spokeswoman said.
Further arrests are expected in
"The people involved in this kind of activity have a certain arrogance -- they think they are untouchable," said Sharon Lemon, SOCA's Deputy Director of E-Crime.
"The message today is that no one should feel confident that these forums are a secure place to operate."