Ian Jelf wrote:

Out of interest would that prevent there being - say - two "7" routes
going to different places or would it prevent two operators on the same
route sharing the same number? The latter has arguments for and
against, of course.

Personally, I would say it is essential to prevent two different routes
having the same number where those two routes meet at any location
along said routes. Within town areas where it might cause confusion,
I'd extend that to where the two routes exist within the specified area
as well.

Whether two operators share a number on an identical route is a
different matter - if the routes are completely identical (or one is a
short version of the other) it would make sense for them to be the
same, but as you say there are arguments both ways.

If the routes are similar but not identical (i.e. have a significant
common run) it's not quite as clear-cut, but the issue would need to be
considered carefully in each case.

Neil