Online criminals are making millions of pounds by tricking the public to download fake anti-virus software, internet security experts claim today.

Symantec says over 40 million people have fallen for the "scareware scam" in the past 12 months.

The "anti-virus" download is harmful to your computer and criminals can sometimes use it to get the victim's credit card details.

The firm has identified 250 versions of scareware, and criminals are thought to earn in excess of £750,000 each a year.

It appears on your screens as a legitamate pop up and tricks the user into thinking that their computer has been infected with a virus. It then instructs you to pay upto £60 and many users credit card details are then being passed on to be used in other criminal forms. This virus will pretty much hold your computer to ransom, showing inappropriate materials randomly and locking files and pictures stored on your computer. Police have commented and expressed the difficulty in convicting the criminals due to the amounts being so small.