Spammers - the faceless crooks who bombard email inboxes with enticing offers of cheap prescription drugs and pirate computer programmes - have notched up another victory in the global battle to put them out of business.

A recent failed initiative by internet portal Lycos to fight the hate with good old-fashioned free love has ended up creating even more unwanted mail, this time in the shape of a particularly nasty virus.

Lycos's plan was to send the costs of hosting the spam sites soaring and thus make the spammers' operations unprofitable. It did this by offering a screensaver which users could download onto their desktop.

The screensaver, which featured the slogan "Make Love Not Spam" in psychedelic pink lettering straight off the streets of 1960s San Francisco, barraged the spam sites with data, clogging their bandwidth and driving up their hosting costs.

As an added bonus, the spam sites were now operating at a fraction of their normal speed. The screensaver worked off the idle processing powers of a PC, so the user's other operations were unaffected.

Lycos treaded very carefully, promising not to knock out spam sites altogether and taking their list of sites from legitimate anti-spam organisations such as Spamcop.

Mr Kay Oberbeck, a spokesman for Lycos Europe said on the day of the launch that the company understood the risks involved.

"You have to be careful and that is what we are doing," he said. "We want to show the owners of such spam websites that there is massive interest among thousands of users who are not willing to just give up against more and more spam each day."

Mr Oberbeck promised that the sites would not be knocked off completely, as the screensaver would leave them just enough bandwidth to stay running.

"They will never go below 5 per cent bandwidth. Never," he said.

After an initial soft launch in Sweden, makelovenotspam.com was launched across Europe on November 30th.

The operation appeared to be an instant success, with more than 100,000 downloads in the first couple of days after its introduction and reports of the targeted sites running sluggishly under the weight of the attacks.

Things soon started to sour, however.

A few hours after the site was launched, a new message appeared under the slogan, saying: "Yes, attacking spammers is wrong. You know this, you should not be doing it. Your IP address and request have been logged and will be reported to your ISP for further action."

Although this was originally seen as a counter-attack from the spammers, it is more likely to have been a harmless hoax. But worse was yet to come.

The reaction on message boards and blogs was not all positive, with some saying that the campaign encouraged vigilantism and that it was adding to the massive volume of useless data already on the net.

Others pointed out that, while it was all well and good for a corporation such as Lycos to launch an attack, individual users could be left vulnerable to the wrath of the spammers.

Popular discussion sites such as slashdot.org and everything2.com carry considerable weight and any topic posted on these sites will be read by thousands within minutes.

The negative responses to makelovenotspam would have been very influential in the net community.

The factor that really doomed the campaign was the report from net monitoring firm Netcraft that some of the spammers' sites had crashed completely, despite Lycos's assurances.

This raised the prospect of a legal investigation, as the operation was beginning to look like a Distributed Denial-of-Service Attack (DDSA), where thousands of computers simultaneously send data to a site in order to close it down.

Although DDSAs are not explicitly illegal, any investigation would be highly embarrassing for Lycos. It replaced the site with a holding page saying "Stay Tuned" under the original logo, only four days after its launch.

The project has now been officially discontinued.

Lycos claims that it wasn't its fault that some of the spam sites crashed and that it has achieved its aim of bringing attention to the fight against spam.

Cynical observers might say that Lycos has succeeded in bringing attention to itself and its products and that behind the flower-power face of the campaign was a publicity stunt that Lycos knew would never succeed.

It it is true that it would be extremely naive of anyone at executive level in a major internet firm to think that the spammers could be stopped so easily, and it is also true that the project has created massive publicity for Lycos.

That publicity may yet backfire, however. In a final twist, Lycos has had to post a warning on the site telling users that not only is the project discontinued but also that there is a new Trojan horse virus going around masquerading as the makelovenotspam screensaver.

The virus, which comes with the subject line "Be the first to fight spam with Lycos screen", will install a spying programme called Perfect Keylogger, which records the users' keystrokes to collect personal data, such as passwords and details of bank accounts.

Whatever Lycos's motives, the spammers are not going away, nor will they take any future attacks lying down.

According to Mr Graham Cluley of anti-virus firm Sophos, "attacking a spammer's website is like poking a grizzly bear sleeping in your back garden with a pointy stick".