Two nuisance incoming phone calls in the last couple of days to the never-used land line.
Heavy Indian accent, telling me that he was from the technical department of BT and that there was a problem with my line/broadband (or something similar - I hanged up before he managed to go any further).
The confusing thing was that the Caller ID showed a local number - i.e. area code and first 3 digits.
Any idea how they do this? Using more sophisticated software? Is it possible to tell if it was originated from the UK or not?