If the Queen of England used public transportation, she wouldn't have far to walk from her Buckingham Palace home. And finding her nearest stop is now very easy since Transport of London has implemented a Google Maps mashup of bus routes.
Some are calling it best UK Map Mashup Ever. It's well designed and implemented, but you're forgiven if you aren't immediately blown away. To get a full appreciation, consider the previous technology Transport of London used: downloadable PDF maps. The Map Room's Jonathan Crowe called them "some of the most confusing system maps I've ever seen." And he's seen plenty of maps.
It's a big step forward for one of the world's most notable cities. And hopefully a sign of open transit data on the way. London is remarkably still not included in the Google Maps website transit directions. If the Queen did use public transportation, surely she wouldn't stand for that.