When Doug Varey clicked on a pop-up ad offering computer security protection for 12 years for £556, he signed up.

"I had no reason to suspect it wasn't genuine," he says.

That was a mistake. Mr Varey was a victim of a common online scam known as computer software service fraud, which ended up costing him some £4,000.

https://www.bbc.co.uk/news/technology-50117796