Antivirus firm Avecho has launched a unique product for SMEs which it claims can stop all spam messages and email viruses dead in their tracks.

The company was not prepared to divulge details of its so-called GlassWall technology but maintains its claim that the software is 100 percent effective, leaving itself with a pretty big promise to live up to.

Unlike other antivirus systems, it does not rely on detection or scanning.

"We have developed a server-based process where the GlassWall processes every single email rather than looking for a definition file," explained company spokesman Chris Dye.

The system simply stops EXE (executable) files, the main virus carriers, from getting through. Although it says it can adjust the software for companies which need to receive these files, such as program writers.

The technology is provided as an email service, and once the product is registered online the GlassWall kicks in. Users do not need to change their ISP.

The second part of the technology is the antispam filter, which allows users to specifically choose which emails they wish to receive. A content filtering system is also available to block emails containing certain words or pictures.

The SME package provides five email accounts for £75 a year; additional ones can be purchased for £15 each.

Avecho estimates that virus attacks cost UK SMEs as much as £2bn per year.