Whilst online ad fraud is nothing new, in recent years the two companies that dominate the industry have been key targets

Imagine you are a local locksmith in the pre-internet age, and a competitor moves in on your territory, threatening your long established business. To stunt his growth, you may appeal to your local population’s sense of community tradition, or perhaps lower your prices.

You would probably not go to such lengths as getting up early to rip his advert out of every copy of the local newspaper before they are collected from your neighbours’ porches. But in the digital era, you might be able to do something similar.

When people search Google for a locksmith, they are hurried, and likely to choose the first link they come across. Having somebody click on your ad is close to a guaranteed sale, so online locksmith ads are expensive.

If you can arrange for your competitor’s to be clicked on, repeatedly, with no sale at the end, they might end up spending thousands without a single real customer being sent their way. With a few minutes to spare, almost anyone can hire an army of bots and direct them to a rival’s advert.