original topic : http://www.straightdope.com/classics/a2_433.html
Just a quick correction/addition:
The PM’s house is actually a lot bigger than it looks from the outside. The PM also has other properties in the country, and does not necessarily spend their time at no 10 (remember the PM is also an MP for a constituency). I went to school with John Major’s kids, and they lived at their original home. They also have large properties such as Chequers (a large country house) to relax in at weekends.
Also, Cecil notes that having even and odd house numbering on opposite sides of the street is a purely-American thing, and we don’t do that in Britain. That’s basically wrong. Although there are exceptions, the norm is odd on one side, even on the other.
Thanks