In a bizarre spin on the now familiar 419 scam, security researchers today warned of a newly discovered email fraud designed to dupe unwitting recipients into believing they are the beneficiaries of the late Sir Denis Thatcher's last will and testament.

The email, which claims to come from the lawyers of the ex-prime minister's late husband, says that the recipient will receive £950,000 in compensation for work they have done helping the less privileged. The email claims that Sir Denis collected the money during his long and successful career in business.

In order to obtain the inheritance, recipients are asked to provide personal information such as documents of identification, address, telephone and fax numbers, in accordance with the British government's inheritance law.

However, IT security firm Sophos warned that the emails are fake and that users who send their personal details may have their identity stolen, together with money from their bank accounts.

"Scammers are constantly trying to dupe computer users into divulging sensitive information with the promise of big money," said Graham Cluley, senior technology consultant at Sophos.

"Using the late Sir Denis Thatcher's name is a sick trick designed to entice the unwary into falling for the scam."

The email is the latest of many so-called 419 scams, named after the relevant section of the Nigerian penal code where many of the scams originated.

Once a victim has been drawn in, requests are made from the fraudster for private information which may lead to requests for money, stolen identities and financial theft.

Other examples of 419 email scams include a message claiming to come from a persecuted widow of the late Nigerian head of state, an associate of the massacred Nepalese royal family, and even an African astronaut stranded on the Mir space station.