Another scam.
A couple of times I've had someone ring my mobile and say "hello, hello, can you hear me?" in a noisy environment and hang up, as an IT support company I expect to get phone enquiries, the number looks like a mobile, so I returned the call, happily Orange intercepted this and informed me that the number I was dialling wasn't a mobile but was a premium rate line, I hung up before the call was connected.
I'm sick of all the scum that think it's ok to rob the rest of us rather than do an ounce of work, but more than that, I'm disgusted with just how easy Ofcom made it for them by using the same 07 prefix for mobiles and premium lines.