It all depends on where the e-mail was sent from, or which Internet provider was used.

To date, the law covering the Internet is unclear, and there have been few court cases to provide guidance.

But that may change after a series of meetings between the Association of Chief Police Officers (Acpo) and leading UK internet providers (ISPs) who have been looking at how laws apply to the Web.

According to Keith Mitchell, the chairman of ISP group LINX, e-mails sent via Internet providers could be used as evidence, but only if they are sent via companies who are not licenced as telephone operators.

This is because telephone companies are covered by the Interception of Communications Act 1985.

This allows police to tap telephone conversations, but what is said cannot be used as evidence.

Some of the larger Internet providers, such as British Telecom and Demon Internet, are registered as telephone companies.

Many others, including the Microsoft Network, Compuserve and AOL, are not.

E-mail from your company is not private

E-mail sent and received on a company's computer has always received less protection.

Any information stored on a company's machines is that organisation's property - employers can read it and pass it on to police if they wish.

Police can also request that Internet providers pass on information about general traffic patterns - who is communicating with whom - though they are not obliged to provide this without a warrant.

Police 'not trying to circumvent the law'

Detective Chief Superintendent Keith Akerman, who heads the computer crimes subcommittee of Acpo, confirms that he and Internet providers are trying to come up with a set of guidelines.

"The last thing the police want to do is circumvent legislation," he said.

He said the 1985 act is inadequate as it was not designed with the Internet in mind, but he and providers were trying to work out how to apply it fairly.

The police and ISPs will be holding a series of seminars in September and October to look at this and other areas of Internet law.