On 5 Sep 2005 10:27:37 -0700, "Keith Raeburn"
wrote:

I was once told by a controller (in Centrewest London Buses days) that
the busiest in terms of passenger loadings was the 207 (Shepherds
Bush-Uxbridge). This route was recently (April 2005) renumbered into
two overlapping sections (207 and 427), although it had in fact been
running in these separate sections, albeit under the same route number,
for about 20 years.

I'm sure that 207s have been running the entire length of the route at
least at certain times of the week, far more recently than 20 years
ago - the split used to only be a peak time or daytime arrangement.