A British man accused by Microsoft of spamming has told the BBC it is a case of mistaken identity and he will fight to clear his name.
Simon Grainger, who lives on Merseyside, was one of 15 people around the world targeted by the company in what is the most high-profile attack so far on the huge wave of unwanted e-mail clogging up the internet.
But the 43-year-old telecoms engineer insists that, in his case at least, Microsoft has got the wrong man - and he is now in a David and Goliath contest with the US software giant.
The revelation came as Microsoft chairman Bill Gates vowed to continued his battle against unsolicited e-mail.
In a statement to the BBC, Microsoft said it had not received any formal notice that Mr Grainger would be taking legal action to defend himself. But it did leave open the possibility that it had made a mistake.
"In the event that there is persuasive evidence supporting Mr Grainger"s assertions, we would be very happy to consider it and team up with Mr Grainger to discover the true identity of the perpetrators," the statement said.