I just had a call from number +44 2030513739. The guy was telling me that they are from green card lottery and I would have to pay 208 € in order to enter it and fill out an application.
This very number called me at my home phone in Portugal about 5 minutes ago. I didn't answer, as I don't know any entity in the UK which has my home number - there are a few people there with my mobile number but not my home number - so I decided to look it up on Google and I came across this page.
So...it's either a prankster or a scammer, from what I see?