Cybercriminals are flooding inboxes with Halloween-themed spam emails linked to a Trojan computer virus, internet security company Sophos has warned.

The emails direct internet users to a website that purports to offer a download of a dancing skeleton game. However, clicking on the download installs a program that gives the hackers remote access to the user's PC.

Sophos said the malicious emails have a variety of subject lines, including “Happy Halloween”, “Dancing Bones”, “The most amazing dancing skeleton”, “Show this to the kids”, “Send this to your friends” and “Man this rocks”.

Graham Cluley, senior technology consultant for Sophos, said: "This is just the latest incarnation of the e-card campaign, which has dominated the malware scene for months.

“The gang responsible are experts at choosing topical disguises and crafting alluring emails that the unwary may find difficult to resist."

To keep safe online, users are advised to only open emails from contacts they recognise and to be wary of unknown websites and links.