A fake anti-virus app which managed to secure a user rating of 4.7 out of five stars topped the Google Play chart – despite offering no actual functionality.

According to Android Police, the app, called Virus Shield, does not offer any security features, with its sole feature being that an “X” image is switched to a tick after a single click. While this replicates the standard symbols for “not protected” and “protected” in antivirus software, in this case it is all that actually changes.

Citing data from Appbrain, it was reported that the app had taken the number one paid new app spot, with more than 10,000 downloads at a cost of $3.99 each.

Android Police said it drew its conclusions after decompiling the app. It described the product as “such a brazen and expensive fake that we felt the need to give it some special attention”.

While the openness of Google’s Play ecosystem is generally perceived as its strength, it does mean that it is more open to abuse than a heavily-curated system such as Apple’s App Store.

Google has been taking steps to improve Play, including the introduction of technology to scan apps for malware, and preventing developers from issuing updates beyond the Play mechanisms which could alter apps already installed on devices.

But Virus Shield does neither of these things, meaning there is little to trigger the alarm bells in an automated system.