Annie Mole's, webmaster of Going Underground, daily web log (blog).
If you like this you'll LURVE One Stop Short of Barking, THE fun and informative BOOK about travelling on the London Underground.
See if you can discover what it is before they correct it (Clue - it's in the section I've linked to above) hopefully it's not made it to the new printed versions out tomorrow!
No prizes, just the satisfaction of knowing you're right!
Update - Just had an email from the press desk of LU who said "Thanks for tip re map mistake, now resolved. Fortunately supplier error didn't make its way on to hard copy poster and pocket maps ..."
"The magic, mystery & sometimes maddening shortcomings of London's Tube are documented with love, enthusiasm & sometimes despair by its unofficial social historian." The Guardian