The Metropolitan Police is warning the public to be aware of a computer virus that impersonates its e-crime unit in an effort to steal money from unsuspecting users.
The malicious software infects people's computers after users access certain websites. The police did not name specific sites, and only said that "various websites" were affected.
Once infected, the virus freezes and locks the PC, and a message (pictured) claiming to be from the Metropolitan Police Central e-crime Unit (PCeU) accuses the user of accessing pornographic websites and tells them that they have to pay a fine to unlock their computer.
"This is a fraud and users are advised not to pay out any monies or hand out any bank details.
"Genuine law enforcement agencies would never contact members of the public via this method and demand funds in this way," the police said.
People who have fallen for the scam and handed over money should report the matter to their card issuer immediately and report the offence to their local police by dialling '101' or the local non-emergency police number.
Virus infections where no money has been lost can be logged at www.actionfraud.police.uk/report_fraud.