Are you sure about that google?
Sometimes google maps gets things wrong. Nothing important obviously, but if you take a look at this bit of the map.... Look at the little details... Squint your eyes and concentrate now...
Vauxhall station is on completely the wrong side of the river! (This was since fixed but only after several months of wrongness)
Obviously that's a pretty serious navigational problem. Do you link to google maps when you email a friend with directions? Are you using google maps on your website? If you do this in the Vauxhall or Pimlico area you may not be being as helpful as you thought you were. Maybe it's time to use a better map, the open licensed map from the London-born not-for-profit OpenStreetMap.