Internet service providers (ISPs) are drawing up a list of what they will tell the police about their customers when under criminal investigation, and how much they will charge for the information.

The move is an attempt by ISPs to resolve one of the factors in the row between them and law enforcement authorities (LEAs) about who will foot the bill for the implementation of the so-called snooping act, which passed through parliament last year.

Tim Snape, managing director of a small Dorset-based ISP, said the list contained simple, common sense questions that ISPs believe they could be asked by LEAs in the course of investigations.

Another list, of what each ISP will charge to answer each question, is also being drafted. Details of both are due to be published in the near future.

Snape spoke at the Internet Service Providers Association's (ISPA) fifth annual Parliamentary Advisory Forum, held at the House of Lords, where ISPs, members of parliament, government officials and law enforcement officers met to discuss internet issues.

The meeting was dominated by issues surrounding the Regulation of Investigatory Powers (RIP) Act, the so-called email snooping bill which gives the police and other LEAs the power to requisition data.

Currently, ISPs help the police on an ad hoc basis but have become frustrated by enquiries from officers ignorant of both the internet and the legislation relating to data contained on it.

At today's forum, Mark Gracey, legal liaison officer with Thus, owner of Demon Internet, said half of his dealings with the police involved educating them about what information they could ask for under what legislation, or explaining basic internet questions such as "what is a hotmail account?"

Other ISPs said they were fed up with being asked "stupid" questions and blasted the police's lack of knowledge.

Of his experience of helping local police forces with their enquiries, Tim Snape said: "My children at primary school are better trained in the internet than the local police."

As well as human interaction, ISPs believe the technical cost of helping the police could place an impossible strain on their businesses.

ISPs want a system, called data preservation, where police forces identify a suspect and notify the ISP, then the ISP keeps track of the suspect's communication. Police and other LEAs want to be able to search archived stores of emails that a suspect may have sent, a system called data retention.

Estimates of the cost of a data retention system vary greatly depending on what criteria is applied to what information the ISP can be asked for, and what steps it will need to take to deliver that information.

Much of this is still being discussed between government officials, ISPs and LEAs. However, ISPs have been spooked by rumours of them being required to log all communication data for seven years, the cost of which would run into millions.

Roger Gaspar, deputy director general of the National Criminal Intelligence Service, said the police had never asked for data to be retained for seven years, and that LEAs couldn't reasonably argue the case for data to be retained for more than three years.

ISPs currently reject the idea of them contributing towards the cost of any data retention system.