Within days of the terrorist attacks on London's public transport system, security experts have intercepted a Trojan which promises video footage of the atrocities in a bid to trick unwary recipients into opening infected attachments.

Antivirus company MessageLabs reported on Friday that it had caught a piece of malware that spread itself in an email with the subject line 'TERROR HITS LONDON'.

The body of the message resembles a newsletter from CNN and promises the receiver "unique amateur videoshots" if the attachment is opened.

Instead of playing a video, the message copies itself to the user's system and accesses a list of preconfigured email servers. The Trojan then uses these servers to start sending spam email messages.

Authors of Trojans and viruses often use current events in an attempt to help spread their malware.

Last month a Trojan promised further information about the alleged suicide of Michael Jackson, and movie star and California governor Arnold Schwarzenegger has been used in the past to spread computer viruses.