Danger is lurking in your inbox. According to the USA's biggest consumer body, the fastest growing internet fraud is sent via email.

The National Consumers League's survey, conducted in April, revealed a massive 94 percent of the 28,655 respondents had received unsolicited email offers.

"While not all unsolicited email messages are fraudulent, consumers should be very suspicious of anyone who promises them easy money, incredibly cheap prices, or 'free' services that may have hidden costs," said Susan Grant, director of NCL's Internet Fraud Watch foundation.

The most popular worldwide email scams are known as 'Nigerian money letters'. Yesterday, six men were arrested in South Africa in connection with these fraudulent emails.

"The person offers you millions to hold money in your bank account temporarily, but it's a pack of lies," said Grant. "There is no fortune, and the purpose of the scam is to take money out of your account, not put it in."

Just over a third (32 percent) of people said they had received credit card offers in their inbox, 27 percent received invitations to X-rated sites and 12 percent had received Nigerian Money offers.

"Junk mail is usually easy to spot," said a spokesman at the Consumers Association. "People should delete any offer which sounds too good to be true or, better still, delete any email they don't recognise."

Those Top Ten Internet frauds for 2001 (in full)

1. Online auctions — where items were misrepresented or never received after being sold

2. General Merchandise — again, items paid for but never received

3. Nigerian money offers

4. Computer equipment and software — paid for but never received

5. Internet Access Services — charges from ISPs that were never requested

6. Information/Adult services — charged to credit cards when the service was never provided

7. Work at Home Schemes — kits sold with false promises

8. Advance Fee Loans

9. Credit Card Offers

10. Business Opportunities — exaggerated claims of potential profits through investments