Paul Scott wrote:

much as it might seem straightforward to have a London centred zonal
system spreading ever outwards, there will have to be a limit somewhere -
and it might as well be the Greater London boundary as anywhere.

Actually ... I rather like the idea of the zones spreading ever
outwards. With Zone 43 including the great arc of Wrexham, Chester,
Warrington, Manchester, Huddersfield, Leeds and Hull, it looks like a
one-zone ticket will be quite good value, though knowing the way that
such boundaries are set, I expect a Chester to Manchester via Knutsford
ticket would have to be a 2-zoner. ;-)
--
http://gallery120232.fotopic.net/p9632915.html
(40 024 at Reading, 17 Jan 1981)