Brightmail's technology uses a network of decoy email accounts, with a reach of more than 100 million inboxes, to attract and identify spam.
Filtering software is then used to check all of these email accounts every five minutes and remove any signs of junk mail. All junk is stored in a separate folder for 30 days before being deleted. At this point, any emails containing viruses are also cleaned using technology from antivirus firm Symantec.
But there are additional steps non-Openworld customers can take to cut down on the level of spam in their inboxes.
"Always go to an ISP that offers antispam solutions and use multiple email addresses for different purposes [for example one for work, one for shopping]," said Enrique Salem, CEO at Brightmail.
Unfortunately, Salem says, it is extremely easy for spammers to get hold of an email address.
"Every time you go on the internet or send an email you are effectively making your address public knowledge," he said.
EU legislation, which will provide an opt-in approach to junk mail, will do little to resolve the problem, according to Salem, as most spam is sent from outside Europe.
"It's good that governments are pushing through this legislation but in order for it to stop spam every country around the world would have to back the legislation, which is almost impossible," said Salem. "But what this legislation will do is create an offence with which to charge people [within the EU] if they do break the rules."
The real issue seems to be who should be responsible for stopping spam.
"It makes sense that it's the ISP's duty as it is far easier for them to stop it than it is for the [end user]," said Salem.
The service will be available to all BTopenworld broadband customers by the end of October and rollout to BT's dialup narrowband customers is expected before the end of the year.
Microsoft's Hotmail service will be announcing a similar partnership with Brightmail later this month, according to Salem.