A new and highly plausible virus has been released onto the Internet.

This particular virus is travelling in an e-mail which bears the subject line: "TERROR HITS LONDON" and comes from a spoofed e-mail address.

The body of the message tells those receiving it to click on the attached file which claims to show amateur video footage shot in the London Underground immediately after one of the bombs went off.

A file called "London terror moovie.avi" is attached to the malicious e-mail. Hidden after a long series of blank spaces is the real title of the file that is attached.

An attempt has been made to make this look harmless by giving it the name: "Checked by Norton Antivirus.exe".

Anyone clicking on the file will not be shown a video. Instead their PC will be infected by the as yet un-named Trojan.

Next time the compromised machine is started, it will report in to the virus creator and become part of a spam-sending zombie network.

Because it relies on people clicking on the attachment, the malicious program can affect Windows 2000, 95, 98, Me, NT, XP and Windows Server 2003