Mobile fone scam
Maybe an old chestnut, but i've had 2 attempts on my phone in a week (no i didn't fall for it, I'm not as silly as I look!)...
Phone rings, caller hangs up as soon as you answer. You call back to see who it was and it's a marketing company and you've just called them on a premium rate number!
number is 08700 426655
ignore it.