When you're training for the Knowledge, which qualifies you to drive a London taxi, it takes over your life. I spent just over two and a half years doing it, during which time I forgot about watching TV and didn't have any social life. You have to remember all of London's 25,000 streets and roads, after all, as well as all the city's major points of interest.

First, we do something called the Blue Book, which is 320 runs that take you all the way around the city. The first run is Manor House to Gibson Square. You start by spending at least an hour and a half driving round Manor House station, learning the area. After that, you drive on, past eight different places of interest listed in the book, discovering how to get in and out, and making notes. Then at Gibson Square, you explore the area again.

In between runs, you do something known as "calling over". In a group of two or three people, you sit around a map on a table and ask each other to describe the quickest route between two places. Then you look at it on the map, and work out if you've gone the correct route. You just keep going over the same thing again and again and again until eventually it sinks in. It helps to do it with other Knowledge students; trying to practise with your partner is the quickest route to a breakup.

We also try to make places more familiar by learning a bit about them, so I read books on the history of London. Now, if someone hails my cab and says, "Take me to Westminster Abbey", I just think, OK, Westminster Abbey's there – it's north, south, east or west – what's the most direct route? Then I'm off driving. You've basically got as long as it takes for them to get round to the passenger door, open it and sit down. I do it so automatically now that I rarely even think about it. London feels a lot smaller as a result. Do I ever get stumped? Of course I do, occasionally. But that's how you learn, isn't it?

• Peter Allen is a taxi driver and Knowledge tutor