UK government officials have promised not to force internet service providers (ISPs) to retain records of which websites their customers browse, what newsgroups they read and to whom they send emails.

Officials from the Home Office and the Department of Trade and Industry made the promise on Wednesday during a meeting with the ISP Association (ISPA), the London Internet Exchange, telecoms companies and the Confederation of British Industry to discuss new anti-terrorist laws.

"The government confirmed that data retention would not be mandatory," said the ISPA. However, although the proposed new anti-terrorist laws won't be compulsory, ISPs will be asked to sign up to a voluntary code of practice to clarify how long certain types of data can be retained.

This could, in effect, still mean that ISPs will monitor customers and store traffic records for up to 12 months. More meetings have now been scheduled to discuss the proposed code of practice.

The ISPA has said it wants to know how the government thinks data should be handed over, how the extra cost of storing records will be met and how the new laws will relate to firms choosing to locate their servers overseas. Previously, some ISPs had threatened to relocate if laws become too intrusive.

Earlier this week, analyst The Yankee Group said that the government would have to dilute its proposals because of the cost implications for ISPs and opposition from privacy campaigners.

In a research note, from Andy Greenman, Yankee's Internet strategy analyst, he said: "We expect the proposed changes to be watered down in light of the current weak state of the ISP market, and the UK government's announced commitment to a wired Britain."

The analyst added that it may be a considerable length of time before the anti-terrorist measures will have any impact on ISPs, as European Union legislators are also considering the issue.