Getting Strange Popups

Hi all.
Now recently I've been getting this really strange popup always asking me to download 360 Security, it randomly pops up on the home screen. I haven't downloaded any dodgy apps recently or downloaded anything off the web. I've tried various Virus/Malware software and don't find anything. I downloaded some Adpush apps some crashed midway and some found apps that I've used for ages to be the problem.

I deleted some apps that I thought might cause the problem but it still happens. It's slightly worrying and no idea how to get rid of it.

Here is a picture of my problem - http://i.imgur.com/Wrzg6A5.png

Thanks,
Chewy