If you happen to be a customer of freedom2surf, a reasonably priced, medium-sized broadband ISP in the UK, then you may, upon trying to set up your connection, encountered some difficulties. Two important things they don't tell you are:

1. You need to set up a dial-up connection, not any kind of broad-band connection. Yes, I know it's broadband, but that's not how it works. Don't spend 30 minutes working this out.
2. Once you've worked out that it's a dial-up connection, it will ask you for a number. "But it's broadband!" I hear you cry, "there is no number to dial!"
   Yes there is. That number is 0,38 including the bloody comma. Don't spend 2 and 1/2 hours working that out. Wasting that much time finding out something that should be fucking written down somewhere on their fucking website might get you seriously fucking annoyed if that were the case.

Much thanks to the good people of freedom2support.net (why can't companies ever make help sites worth half a damn? Why are community sites so much better?) And in particular this thread which, over torturously slow dial-up, eventually answered my question.

(How did I get the dial-up number? By Googling for it from my mobile phone, of course. Honestly, it was like firing an arrow with a thread to lift a rope to lift a chain. Nightmare.)