Dear Honourable Friend. Those generous Nigerians who e-mail you with promises of a fortune are themselves being targeted in a new drive to deter cyber criminals.

Millions of internet users have received messages offering them a huge financial reward if they help to release money trapped in a foreign bank account. And, although the majority of these e-mails are deleted, the fraudsters still find a sufficient number of gullible Britons to cost the country millions a year.

Nigeria’s anti-corruption police have now joined forces with the world’s leading technology companies, including Microsoft, to create a system that will warn e-mail users when they are the target of a scam.

The Economic and Financial Crimes Commission (EFCC) says that the operation has already shut down 800 e-mail addresses used by the criminals to send messages and has uncovered 18 fraud gangs. Farida Waziri, head of the commission, said that it would have the capacity eventually to track down 5,000 e-mail addresses used by the criminals every month and be able to warn 250,000 potential victims at a time. Ms Waziri said the aim of Operation Eagle Claw was to take Nigeria out of the Top Ten list of countries with the highest incidence of fraudulent e-mails.

Cynics will suggest that the ever-resourceful internet conmen will simply find new ways to avoid the regulators. It is probably best not to reply to a message warning that you have been targeted by a scam — particularly if it requests details of your bank account.

The so-called 419 advance-fee frauds, named after the relevant article in Nigeria’s penal code, involves fraudsters asking for money to pave the way for the release of a much greater sum.

Experts have estimated that the criminals receive just one reply from every 12.5 million e-mails they send. But the rewards can be massive.

Social networks such as Facebook have been hijacked recently by the fraudsters, who have taken over the accounts of users and then asked “friends” to send money to help them out of a crisis.

Microsoft said it was working with the EFCC on internet security and piracy and several Nigerian investigators have already had internet forensics training at the company’s headquarters in Washington State. The Nigerian Government is also working with Yahoo! and Google to monitor online traffic.

Graham Cluley, of Sophos, the internet security firm, said any move by the Nigerian Government to clamp down on fraudulent e-mails was to be welcomed. He added that the 419 attacks were becoming increasingly sophisticated.

The Serious Organised Crime Agency in London has also been working with Nigerian authorities to stop fraudulent e-mails targeting the UK.

The Nigerian Government is keen to counteract its image as the epicentre of 419 scams. Last month it banned the film District 9, which depicts Nigerians as gangsters and cannibals, and demanded an apology from Sony after a PlayStation advert implied they were fraudsters.

The tables have already been turned on the fraudsters by a group of British internet users who trick gang members into carrying out ridiculous tasks.

In one elaborate sting the 419eater.com website persuaded a conman seeking £2.5 million to hand over his own money and produce a photograph proving he had joined the fictional Holy Church of the Painted Breast.

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