Adrian Simpson wrote:

On another occasion when I got one, it was from a mate
of mine in Cheshire. Knowing he gets about a bit, I asked him where he
was calling from, to which he replied "home". Turns out that he had
some cheap calls deal with Wanadoo, so they were probably being routed
via France.

Calls made to my BT-line from Skype also show as 'International'

--
Adrian C