Managed security services firm Activis has warned that government emergency anti-terrorists could impose unbearable costs on some internet service providers (ISPs).

The Home Office Secretary is readying legislation that may ask, or even require, ISPs to retain or keep records of which websites their customers visit, what newsgroup articles they read and who they email, for up to 12 months.

John Cheney, managing director, Activis UK, said: "According to research by IDC, by 2003 there will be more than 20 billion emails circulating the internet worldwide every day. If the average size of an email is 2K - a conservative estimate - and ISPs have to store emails for a year, then that equates to a global storage requirement of almost 7000 Terabytes [7,128,906,250 megabytes] needed in storage alone."

Cheney added: "It is unlikely that ISPs would foot the cost needed for the extra storage. Ultimately, it will be passed on to the consumer and that could mean the end of the 'free' email service.

"The other issue to consider is the administration of such a system. Again, it is unlikely that the government will employ people to do the forensic analysis, so the cost of this will again lie with the ISP."

Business communications service provider Nextra UK has added its voice to the criticisms, and said that it would pass some of the extra costs to consumers if it had to keep web log records for 12 months.

The government has said it will consult with IT industry representatives over the issue.

ISPs have been retaining records since 11 September at the Home Office's request, and last week indicated to vnunet.com's sister publication Computing their willingness to hold records for up to three months.

However, they have long been opposed to the retention of logs for any significant period of time.

Data records retention has also split Brussels, with European Union ministers and European Commission officials adopting opposing positions.

EU ministers are backing law enforcement authorities' demands to extend laws to aid criminal investigations, while the EC supports the position of civil rights groups and carriers/ISPs, which have argued that current laws suffice and that the proposed extensions go much too far.