London Cabbie Knowledge

Is THAT what they're doing?! Sorry if I'm being thick here, I always wondered what blokes were doing on the moped's with little mapped areas in front of them.
Wow, that's actually quite interesting despite the fact that the end result is next to useless for me.

Oh for pity's sake. What did you think they were doing? Checking the accuracy of the Ordnance Survey? Retracing the steps of celebrity prostitutes? Lamp post spotting?
And you can see me in my office tomorrow to explain that apostrophe too.