Families should ensure that scam artists are not preying on their elderly relatives, a charity gave warning this week. Seven out of ten pensioners are targeted by a scam every month, with victims losing an average of £1,261 each, according to Help the Aged.

The most common scams include bogus sweepstakes and lotteries, get-rich-quick schemes, fake health cures and competitions enticing victims to call premium-rate numbers. Rachel Corry, of Help the Aged, says: “There are many unscrupulous scam artists who happily take advantage of the vulnerable. Anyone with elderly relatives should tell them never to disclose personal information, especially bank or credit-card details, unless it is to a trusted source.”

People who fall victim to these scammers are highly unlikely to gain redress. Gordon Lishman, of Age Concern, says: “Anyone can be a victim of fraud but, unlike other crimes, you will receive minimal support from the police and no payouts from insurance companies.”

Here are some of the main scams to look out for.

Share scams

Many fraudsters, usually based over-seas, target people listed on the shareholder registers and offer to sell what turn out to be worthless investments.

Such companies may offer free “research” into the shares. The UK freepost address on the return envelope is likely to be a forwarding address overseas. Anyone who reponds will go on a so-called “suckers list” and will be bombarded with calls and letters from scammers.

Sometimes elderly shareholders also receive calls offering to buy their shares, usually at a higher price than the market value. The intended victim will be asked to pay an “arrangement fee” in advance. Anyone who hands over money will never get it back and never hear from the fraudster again.

Experts suggest that before dealing with any financial services company, it is advisable to check that it is registered with the Financial Services Authority (FSA) at www.fsa.gov.uk. The FSA website also provides a list of unauthorised firms operating in the UK, but this is by no means exhaustive.

Competitions and sales

A popular scam targeting the elderly involves sending letters saying that the recipient has won a prize in a competition or lottery that they have not even entered. The intended victim is asked to pay an “administration fee” before collecting the “prize”, which will be either non-existent or worth much less than the fee.

Other competition scams ask victims to call a premium-rate number (this starts with 090) to claim a prize - usually a free holiday abroad. Often the prize does not exist, or is worth less than the cost of the call, which will be charged at £1.50 a minute.

Bogus clairvoyants or psychics may also write or call, asking for money to disclose their predictions. Catalogues for miracle health cures, pills, lotions or vitamin supplements are also common, but if any are ordered and paid for, they rarely appear.

Fake charities

Many fake charities send letters or knock on people's doors asking for donations, with victims persuaded to agree to regular direct debits. To check that a charity is registered, contact the Charity Commission on 0845 3000218, or search the register online at www.charitycommission.gov.uk.

E-mail scams

The internet provides scammers with a cheap way of reaching tens of thousands of people. A common scam is an e-mail purporting to be from someone needing help to transfer a large amount of money to another country. A percentage of the money will be promised in return for the help, but this is an elaborate story to obtain the victim's bank account details.

How to keep out the scammers

Phone: To help to prevent nuisance calls, BT customers can join BT Privacy. Register online at www.bt.com/privacy or call 0800 800150. This places you on an opt-out register so that you should not receive unsolicited calls.

E-mail: Ensure that your e-mail account is protected with anti-spam software. Always be wary of unsolicited e-mails and never reply to any asking for personal details.

Post: The Royal Mail has “a legal obligation to deliver all mail as addressed”. The only way to stop scam letters is to ask for all post to be redelivered to another address - a family member's, for example.

Case study

Geoff Swinton fears that he has lost £12,000 in an elaborate share scam that started with a cold call to his home phone.

A broker under the name of Chartwell Financial Services (CFS), based in Switzerland, offered to sell 15 Apple shares at $157 each and, later, 150 Visa shares at $60.80 each. On both occasions Mr Swinton, above, wired the money to an account in Spain. He received an invoice but no share certificates. Worse still, he paid for the Visa shares twice, after being told that he had sent the money to the wrong account. He has tried to get back his money with no success.

In April the Financial Services Authority (FSA) said that the Swiss Chartwell is not a registered company. There is a Chartwell Financial Services in Cheshire that is FSA-registered and has no association with the Swiss organisation.