A new warrior in the battle against spam has attracted a group of prominent investors and early adopters.

Investors in Bright Light Technologies, based in San Francisco, include Compaq chairman Ben Rosen, former Informix duo Roger Sippl and Phil White, and venture capitalist Esther Dyson.

Helped by such backing, the company has won four leading internet service providers as beta test partners - AT&T Worldnet, Earthlink, Concentric Network and USA.Net. It plans to expand its services to countries where spam is particularly problematic.

Bright Light's pitch to ISPs is that they can outsource their anti-spam effort. The cost of the service - about $10,000 per year for every 2,000 email users - will be justified by the bandwidth made available.

There are several elements to the Bright Light system, which is called Bright Mail.

First, its Probe Network sets up email addresses for the sole purpose of receiving spam. Probing the addresses creates an early warning system to detect incoming junk mail. If spam is detected, details are delivered to the Bright Light operations centre for evaluation by employees on 24-hour shifts.

The operations centre sends updates to the company's Spam Wall filtering software engine, installed at each customer's location, which will block the junk email.

Bright Light says since most spam attacks take hours or days to complete, there is time to detect them and develop and execute counter measures.

Director of internet operations at Earthlink, Steve Dougherty, said: 'We have declared war on spam and Bright Mail should help us further control it. And because Bright Mail is fully outsourced, it offers us a cost-effective, secure way to combat spam while we focus on developing our services in a growing market.'

Bright Light said the system has the advantage over its rivals that it does not rely purely on technology. It claimed to 'keep human brains and eyeballs - which remain the best anti-spam system' in the decision making loop.

The company has aspirations to sell its services to corporates as well as ISPs and says Bright Mail works with most high-profile messaging systems.

Mail providers Sendmail and Software.com are technology partners.

Chris Madsen, Bright Light director of business development, said the company had plans to replicate the operations centre, which has about 15 employees, on other continents in order to offer the service internationally.