The 10 biggest scams to watch out for

That does not stop otherwise sensible people losing their heads - and money. One Kent reader filled in a "European Tourist Industry" questionnaire and was soon told he had won €985,000 (about £800,000) on Euromillones. He sent £1,950 to cover "transfer costs". Then he was told "it was blocked by the Spanish government" and that meant a tax bill.

"I then woke up. I realised there was no tax bill and the insurance protection payment demanded was a total phoney. I've written off the £1,950 - we live and learn," he says.

Easy to lose £2,000 to £20,000.

·Phoney psychics

The only thing these people predict correctly is that vulnerable people will send them cash in response to mailshots which contain a mix of menace - you could die or fall ill if you don't respond - and reassurance such as "you'll be safe and will win on the lottery" if you send off the money for this. These are usually sent by post - often targeted at elderly people whose details are sold and resold.

Easy to lose £20 to £50 many times over.

· Mail-order brides

This is really sad. Scamsters look for lonely people - usually men - and offer them love on the internet or by post. The "beautiful" women, who often claim to be Eastern European or Asian, don't exist: what victims see are pictures copied from entertainment, fashion or celebrity magazines.

Once smitten, men are asked to send their lovers money for air tickets, cash for "the family" or even amounts to pay off old boyfriends. To keep them interested, the targets may be sent sexy pictures or intimate clothing items. Victims are strung along until they realise they have been stung - or until they run out of money.

Easy to lose £2,500 to £25,000.

·Boiler rooms

Persuasive salesmen (almost never women) cold call investors and try to persuade them to buy shares or commodities on the promise that "they will double or treble your investment in three to six months".

The sales pitch may have a pinch of truth, but what is on offer is phoney. Investors are often shuttled between "analysts" and "senior analysts" but these titles are meaningless.

The shares are usually in companies that don't exist, while those bets on currency exchange rates or heating oil are never made - often the boiler room tells victims they have quick gains, to encourage them to invest even more.

These profits are not real; and even if they were, boiler rooms do not ever send "winnings" to investors. The FSA website has a partial list of boiler rooms but there are many more.

Featured in US television series The Sopranos, many boiler rooms are linked to organised crime families.

Easy to lose £10,000 to £100,000.

·The Nigerian or 419 scam

When the "widow" of former Nigerian dictator Sanni Abacha emails to ask your help in getting access to the odd $35m or $60m that happens to be locked in a bank account, most treat it as a joke. Using various names, this scam (named 419 after the section of the Nigerian legal code that outlaws this) has been around for at least 30 years. While Sanni Abacha was real, and the fact that those in corrupt regimes stashed away money in offshore banks is not disputed, the widow is a total phoney - as is the promised bank account.

This is really another version of the "advance fee" fraud. Those who fall for this - and enough do to make it a well-paying proposition for fraudsters - are told to send a few thousand for "taxes", then more and more until victims run out of money or patience.

Easy to lose £20,000 to £100,000.

·Land banking

Here you are persuaded to pay around £10,000 for a tenth of an acre in a field - which the seller has bought for about £7,000 an acre - on the promise the land will soon receive planning permission and soar in value. So far, no land banking site has ever gained the building go-ahead.

Most land sold in this way is green belt or zoned for agricultural use only. But land bankers seize on every government statement about the need for more homes to stress that this means that it is certain that the site they are selling will soon be covered in houses - like almost all scams, this relies on an element of truth. The FSA has shut down a number of these firms, but victims generally lose their money.

Easy to lose £10,000 to £25,000.

·Ostrich farms

Along with claret, champagne, and single malt whisky scams, ostrich farms exploited victims who believed that the commodity would profit from rarity. But the same ostrich was sold over and over - and the expected market for ostrich meat never happened. Equally, champagne and scotch firms are quite capable of expanding output ahead of an event such as the millennium. Those who bought champagne at top prices found they had very non-vintage fizz - if anything at all.

Easy to lose £4,000 to £40,000.

The next big thing?

Some scammers tell Money they are now working out how to rip off the unsuspecting via carbon trading - the appeal is a mix of environmental responsibility and appeal to greed. Don't fall for it.

How to Avoid Scams by Tony Levene is published by Age Concern Books priced £9.99. All profits go to Age Concern.