Cyber criminals that prey in chat rooms will be tracked down in an initiative lead by Jack Straw, the Home Secretary.

A new National Hi-Tech Crime Unit was launched by Straw yesterday. At a cost of £25 million to the taxpayer, the operation will track down criminals including fraudsters, hackers and molesters operating in cyber space.

The unit consists of 80 law-enforcement specialists who will be based throughout the country. It has four main divisions: investigation; intelligence; support and forensic retrieval.

Civil liberties Civil liberties groups are concerned that the new unit's powers will allow it to read private emails without proper authority.

Yaman Akdeniz, director of the non-profit Cyber-Rights and Cyber Liberties organization, said: "I haven't been convinced that there is a substantial need for this unit. I believe child pornography is a serious crime, but it is not an Internet-specific problem."

Crime is crime Lars Davies, lecturer at the Centre for Commercial Law Studies at the University of London, agrees. He said: "There is no such thing as online crime. There is crime full stop. A criminal offence such as hacking, while done on a computer, is still a crime.

"Paedophilia is a horrific crime, but it must not be used as an excuse to give the police extra control over a medium.

"What happens if a person logs onto an Internet address by mistake, and ends up on a paedophilia site? Will he immediately be flagged down? And how can he prove that he never meant to visit the site?"

However, Fleur Strong, spokeswoman for the National Criminal Intelligence Service, said: "Police have neither the time or the inclination to search through individuals' email. This unit is looking at serious and organized crime."