Campaigners against spam on the internet have won a major battle against the world's second largest internet service provider.
Spammers will no longer be using Savvis as a route to inboxes
US firm Savvis was allegedly earning up to $2 million a month from 148 of the world's worst spammers, a former employee had claimed.
Following talks with anti-spam groups, Savvis has now promised to get rid of the spammers using its network.
The move has been welcomed by anti-spam campaigners and organisations.
Savvis has a low profile publicly, but on the net they are a big player.
The company describes itself as "the network that powers Wall Street", because it provides the network connections for the New York Stock Exchange, as well as many other major financial institutions, including 75 of the world's top 100 banks.
Until this year Savvis was regarded as a model service provider with a strong policy against spam.
But in January it bought C&W US, the American arm of the British telecommunications company Cable & Wireless, for $155 million (£87.4 million).
Along with C&W US's 3,000 business customers, Savvis inherited 95 major spammers who make their money by sending out millions of unsolicited e-mails a day with the standard mix of Viagra and porn offers.
Since then they have added another 53 spammers, bringing the total number of spammers on their network to 148.
Just from these customers alone the company was making a reported $2 million (£1.1 million) a month, the former employee had claimed, a figure which Savvis disputed.
But internal memos sent between Savvis executives, and seen by the BBC, referred to the spam customers and how much money was coming in from them.
As rumours about Savvis and the spammers grew on the internet, executives discussed different ways of keeping the customers and whether they could hide them by changing their names or their computer IP addresses.
One memo, from a senior Savvis executive in charge of Information Security, warned fellow management that the company was in danger of losing its good reputation and a secure and honourable provider.
He warned that they could lose their ability to sell to upstanding customers.
Alif Terranson, a former Savvis employee who was responsible for keeping the network clean, objected to the spammers and wrote a 200-page report detailing his complaints about the spammers.
He told the BBC: "One of the Vice Presidents told me, 'Take no action against any Cable & wireless customer - they are profitable and they are off limits.'
"He was talking specifically about that 200-page report which at the time was 95 spammers. When I left Savvis in April it was almost 100, today it is 148.
"In my opinion there's no way they could go and add 60 spammers to their service without actively looking for that business," he said.
Mr Terranson went to Steve Linford, who runs the Spamhaus block list from a small house boat on the River Thames near London.
Around the world 260 million users are protected from spam by the Spamhaus block list, which identifies where spam is coming from.
In three long conversations with Savvis executives last Friday, Mr Linford persuaded them to ditch its spamming clients after threatening to block all Savvis e-mails, making it very difficult for them to communicate with the outside world.
Mr Linford said: "The spammers that they were hosting include some of the worst - Eddie Marin, the spam king of Florida for example, a lot of the Viagra spammers, and a lot of the pornography spammers.
Viagra is commonly offered via junk e-mail
"So there were some very serious spam gangs on there. For us it is a real victory in being able to get the spam gangs off, and at the same time gaining a new ally in Savvis' management."
Mr Linford applauds Savvis for reacting so quickly, and promising to clean up their act. He points out that many service providers would prevaricate, make excuses, and blame someone else to avoid the problem.
Savvis itself says the company is firmly anti-spam, and Rob McCormick, the Chief Executive Officer, told the BBC that Savvis does have an excellent reputation for being anti-spam.
He disputed the figure of $2 million a month revenue from the spammers, and said the actual figure is only a tenth of that amount.
Mr McCormick said the problem stemmed entirely from the spammers they inherited from C&W.
"The previous owner of that company allowed something to exist for a long period of time, and people are expecting that a few months after the acquisition of a bankrupt company it's suddenly our fault.
"Savvis does not believe illegal spamming is good, in fact 99.99% of our customers are large enterprises who are recipients of this kind of stuff, and don't like it either.
"So what we are going to do is shut them off and we are working with Spamhaus to do this."
Mr McCormick promised that within the next 10 days all spammers will be taken off their network.
This will be celebrated in the anti-spam community, a small band of enthusiasts who patrol the net like voluntary cyber cops to eliminate spam, viruses and internet crimes, many of which are linked.
Organisations such as Spamhaus, and Spews (Spam Prevention Early Warning System) are continually chasing spammers across the world.
But as they are thrown off one service provider, there is always another one ready to take them on for the lucrative business they bring.
The volume of spam shows little sign of diminishing. MessageLabs scans 65 million e-mails a day and in August found 84% of them were spam.