MIG wrote in
:

On Mar 8, 9:07*pm, Clive wrote:
In message
,
MIG writesFor Watford and the
Metropolitan (PA
YG accepted) they created zones 7
to 9.

What happened to zones A to D?

Not an expert, but they were replaced with numbers around about the
time of the creation of London Overground I think. Someone will be
along with the correct answer ...

The Font Of All Knowledge states that "On 2 January 2008 zones A-D were
replaced by new zones numbered 7-9."

http://en.wikipedia.org/wiki/Travelcard_Zones_7-9
http://en.wikipedia.org/w/index.php?...card_Zones_7-9
&diff=prev&oldid=181657722