MOVING into difficult territory is nothing new for Detective Chief Superintendent Sharon Lemon, the head of the 50-strong National Hi-Tech Crime Unit (NHTCU). In her time she has run a national firearms team and the biggest internet paedophile investigation in UK history.

She became the first middle-ranking female officer to work part-time as she brought up a young family and is now one of the most senior women detectives in the country.

After nearly 30 years as a police officer, Lemon has become sheriff to Web UK, protecting those — a quarter of the population — who regularly use the internet and contribute to a retail economy worth £10 billion a year.

Lemon saw the nasty side of the internet when working for the National Crime Squad (NCS) on Operation Ore, an investigation of 7,000 Britons who subscribed to a network of paedophile sites. But she does not claim to be a technical expert. “I don’t feel threatened that a lot of the team out there know things I don’t,” she says, and sees her role as setting the vision and parameters for her team.

“I manage first and foremost and there are technical aspects I would not have a clue about, but that is not my remit,” she says. Lemon has never been an authorised police marksman but she set up and ran the firearms unit, used by the NCS for protecting investigations, and has commanded live operations.

Her new team is expected to double in the next year as it comes to grips with the gangs who plunder e-commerce. Last year the unit released findings indicating that companies have lost more than £2.45 billion through hi-tech crime.

The biggest worry for Lemon is the naivety of the public. “People do silly things online that they would never do in any other part of their lives,” she says. “No one would give cash to someone who just knocked on their door and asked for money, or give someone in the street their date of birth or bank account details. But once people get online they lose self-control.”

She is also critical of the jargon with which crimes on the internet are described and worries that it leaves people confused. “Eighteen people out of twenty asked would have no idea what ‘phishing’ was unless they worked in computers.” The word refers to techniques used to gain personal information for identity theft.

There is little doubt that criminals know the potential. The common image is of computer-savvy hackers, but Lemon disagrees. “Most of it is traditional criminals using it for crime with high rewards and low risk,” she says.

There is also the risk of attacks from Eastern Europe and Asia. Two years ago her unit was involved in halting an extortion racket being operated from Russia against online bookmakers. The attackers bombarded the servers with thousands of messages, shutting down the company and costing millions of pounds in lost business. The gang then sent e-mail demands for money to be paid to the blackmailers to stop the attacks.

The gangs are always ready to exploit changes in security systems. Since chip-and-pin technology was introduced to protect card fraud in shops there has been a rise in impersonations of card-holders on the internet. One answer is a campaign, Get Safe Online (www.getsafeonline.org), launched by Lemon’s team, private sector sponsors and government, which offers simple advice and guidance.

She says: “It’s about enabling everyone to get the best out of a fantastic system with the recognition that there are criminals who will look for the opportunity to exploit others.”

Stewart Tendler is Crime Correspondent for The Times

Factfile: Sharon Lemon

Born: 1957, in Central London.

Career: 1976-99 Metropolitan Police (made sergeant in 1982, inspector in 1988 and chief inspector in 1994); 1999 National Crime Squad; became head of the firearms unit in 2000; made superintendent in 2001; became head of Paedophile Online Investigation Team in 2003; became chief superintendent and head of NHTCU last year.

She says: “There is a whole group of people who enjoy using the internet but won’t use it for paying etc because they are scared.”

Little-known fact: Once took part in a job opportunity show on TV with a hairdresser who wanted to be a policewoman.

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive