Spam is said to make up half of the world's e-mails

They are among 17 alleged "persistent spammers" across the world who are being taken to court by the computers giant.

It has accused them of gathering e-mail addresses of its customers and sending them unsolicited junk messages.

The messages are alleged to have told recipients they had suffered a virus attack.

Those who responded ended up giving their own e-mail addresses and those of their friends to the alleged spammers, allowing them to be sent more junk e-mails.

What they are doing is using technology and misusing and hacking into our software in order to gain details of our customers Matt Whittingham, Microsoft

Spam is a problem because huge volumes of unwanted messages can clog up e-mail inboxes, drastically slowing corporate computer networks.

Matt Whittingham, marketing manager for Microsoft's MSN UK division, said the company had announced four initiatives aimed at tackling spam: enforcement, technology, self-regulation and legislation.

He added: "We are taking civil action against 17 persistent spammers, two of which are in the UK."

He said the alleged spammers had been tracked by a specialist Microsoft team, adding: "The two UK cases are quite interesting because what the spammer has done is called 'harvesting'.

'Randomly generated'

"It's basically launching an attack on one of our e-mail servers.

"What the spammer does is send millions and millions of randomly generated e-mails to addresses which, in this case, either ended in @hotmail.com or @msn.com.

"Either the customer or the e-mail server responds when one of those randomly generated e-mail addresses is actually a live address which is attached to one of our customers.