Although I live in western Canada, I started making reasonably regular business trips to London about five years ago. One of my first purchases was a pair of map books:
  • a rather large (12cm x 15cm x 2cm) and reasonably comprehensive London map book that I could just barely fit in my coat pocket
  • a much more compact (5cm x 7cm x 1cm) London Underground map book that consisted of an alphabetical-by-Tube-station-name series of maps of the four or five blocks surrounding the fifty or so most popular/important Tube stations in central London plus a street index for the areas covered by the maps and with a system-wide Tube map on the back cover.
It wasn't long before the comprehensive London map book was staying in my hotel room and I'd settled on a touring style most evenings which consisted of:
  • finding someplace interesting to go in my London Underground map book
  • using the Tube map on the back of the map book to navigate through the Underground to a Tube station near my final destination
  • using the appropriate page from my London Underground map book to find my ultimate destination
This touring style caused me to fairly quickly develop an islands of London metaphor in which the regions surrounding each of the Tube stations became islands and the Tube system became the transportation device that I used to travel between islands (not quite as fast as the one on Star Trek but it got the job done).

As metaphors go, this one worked quite well as it allowed me to ignore the vast complexity of the "London Aboveground" and focus on seeing the sights that I wanted to see. In fact, it wasn't long before I developed a second touring style which I used when I had no particular destination in mind:

  • select an island (i.e. a Tube station) almost at random from the islands of London map book (i.e. the London Underground map book)
  • use the Tube to get to the selected island
  • wander around the island for a while
  • repeat as necessary until it's time to go to bed (most of my London touring was and is done in the evenings as the days are spend "doing business")

I gradually built up mental maps of the twenty or so islands that I visited most often and found that I could often just take the Tube to one of these islands and wander around without needing to refer to the London Underground map booklet much at all.

After a while, something interesting started to happen - sometimes I'd start out on a walk in one island and eventually find myself in one of the other islands. I might not know exactly how it happened but I'd suddenly realize that I'd switched islands (deliberately getting lost is an excellent way to explore London).

As the mental maps of each of the islands grew, they started to merge together and the islands of London metaphor began to gradually fade away. Eventually, I switched to a small shirt-pocket sized map of inner London and left my islands of London map book at the hotel.

These days, the comprehensive London map book stays in the hotel room, the shirt-pocket sized map of inner London is lost somewhere and the islands of London map book has been retired (i.e. it stays home). I havn't carried a map of any sort with me while touring around London for at least a dozen business trips as I've found that I either know how to get to where I want to go or I can figure it out using the Tube system maps and the local regional maps found in every Tube station. If all else fails, I ask for directions or just take a taxi if I'm feeling particularily lazy (I will occasionally check the comprehensive London map book before leaving the hotel but I'm rarely planning far enough in advance for that to be an option).

I found the islands of London metaphor quite useful for the first couple dozen trips to London and I definitely recommend it to anyone trying to "get their feet wet" in London without drowning in the deluge of complexity that is a characteristic of any large city.

One last comment/story: my mental map of London is most reliable in London's West End. When I'm walking in this general area, I never get "lost" yet I often don't know where I am. Here's an example - I recently walked from the British Museum area to Trafalgar Square. This takes one roughly through the heart of the London theatre district, an area that I know quite well. There was never any doubt in my mind that I'd get to Trafalgar Square reasonably quickly and yet I was surprised at least three times by landmarks that I passed along the way (i.e. I didn't always know where I was but I was never lost).