I just had one of the employees of our sister company make fun of me for knowing an area code she needed. Now, I'm the first to admit that I may be slightly to one side of mainstream - there may even be some evidence nearby - but it's good form to consider people sad for the right reasons, surely?

I probably know fewer area codes than most, off the top of my head. I can remember mine and the one I grew up in (where my family still live). I know one or two local to Mum's, and might be able to remember a couple more local to here. I know London (I assumed pretty much everyone did, but after having the Great 020 Argument again with a colleague just now, probably I was wrong). I can guess a few more, which was pretty much what I did with the one the colleague from downstairs needed.

Granted, I know a fair bit about how telephone numbers are structured and I understand non-geographic numbers better than most, but I work on the technical side of telecoms and it sort of goes with the territory.

How many area codes do you lot reckon you can manage off the tops of your heads?