Spammers could find the UK harder going after the country’s most influential ISP organisation, the London Internet Exchange (LINX), agreed tough new anti-spam guidelines on Tuesday.

The new “Best Current Practice” (BCP) code was passed unanimously by LINX members and will now be considered “best practice” for the organisation’s 150 high-level ISP networks.

The guidelines are designed to make it easier to quickly close down spammers who host e-commerce sites on a legitimate network while sending bulk spam via third parties. They also make clear that members should clamp down on sites offering spamming tools for sale.

Despite holding no legal force, the anti-spam BCPs will be used by LINX to exert peer pressure on member ISPs, although it's not clear how many of them already use such codes on an informal basis. However, according to LINX spokesperson Malcolm Hutty, at least one large UK ISP left the meeting resolving to use the new guidelines to change the terms and conditions for customers of its network.

Hutty pointed to the success of the previous anti-spam BCP, agreed in 1999, which he claimed had by 2003 cut the number of open e-mail relays which could be used to send spam from around 20 percent to less than 1 percent.

The motivation for the new BCP had been the rising costs of spam for ISPs, both in hardware and, increasingly, the cost of supporting customers who complained about problems with bulk e-mail, he said. Having a code made it clear to members that there was a minimum standard for dealing with problem customers.

Influential the new BCP might turn out to be but the problem of spam is bigger than LINX, as Hutty admitted. “The Americans don’t necessarily take the same view,” he said of its chances of wider influence.

LINX names ISPs in its membership from Europe and the US, but the bulk are large UK-based networks.

“We will be working to spread this standard beyond the UK at RIPE, Euro-IX and elsewhere. We shall also be asking for support from the UK government at WSIS (the World Summit on the Information Society), OECD and other international forums,” said Hutty.