“Boiler room” frauds of the kind allegedly devised by Paul Gunter and his 25-year-old daughter Zibiah can earn millions of pounds for the criminals behind them.

They take their name from the rented spaces from where salespeople make their telephone calls and target their victims.

To carry out such scams, fraudsters hijack the identities of dormant, publicly traded companies and sell fake stock in them.

Victims are cold-called by fake stockbrokers, who use high-pressure and misleading sales techniques to persuade them to buy shares in the worthless, nonexistent or near-bankrupt companies.

These tactics may include claims that the company is about to unveil an important discovery that will increase the value of its shares dramatically. Hundreds of potential victims — who are often chosen by examining shareholder registers at Companies House — can be contacted in a single day.

It is alleged that the Gunters used about 54 publicly traded shell companies to obtain money in this and similar fashions.

They are accused of conning their victims, including thousands of British pensioners, out of £35 million.

Such boiler rooms are not the only places where 21st-century fraudsters lurk. Modern technology has created new opportunities for conmen and women to target our cash, particularly via the internet.

Internet dating fraud involves criminals luring victims hopeful of a relationship into sending money to banks in Africa. The criminals hide behind false pictures on dating websites, and begin corresponding with their target, only to then claim to have become ill or fallen victim to a crime — often while 'travelling'. The new acquiantance is then asked to send money.

"Phishing" scams involve internet-based criminals sending out e-mails, purportedly from banks, advising the victim that their account details need to be checked. The victim is then directed to a website — apparently that of their bank — where their account details and password are captured by the criminal.

A more recent form of phishing scam is the so-called "evil twin" fraud, which targets wi-fi hotspots. The fraudster sets up a second network in a legitimate hotspot, and when the victim opens his internet browser he is directed to what looks like a T-Mobile home page, for instance, which is in fact a fake. The victim's account details are then captured by the criminal.

Advance fee — or 419 scams — have existed in some form for centuries, and involve a victim being approached by mail, telephone or e-mail, and encouraged to part with a sum of money in return for a substantial share of cash to be paid at a later date. These frauds have become particularly popular among West African organised-crime networks and the name (419) comes from the section of the Nigerian Criminal Code that makes such acts an offence.

Print machine fraud is essentially an advanced 419 scam, and involves fraudsters taking advantage of the fact that in certain industries — printing, for instance — it is common for a seller to request a 10 per cent deposit before showing the buyer the product. The fraudsters will advertise equipment for sale and set up a telephone line — apparently UK-based, but in fact based abroad — which costs 47p a minute to call.

Victims of identity fraud find that their personal details have been stolen — often from a company database — and used to set up new accounts to gain credit in their name. It can take months, sometimes longer, for the victim to unravel the chain of debt that has accumulated, and according to the Home Office the crime costs the UK economy an estimated £1.7 billion a year.

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