"Ant W-M" wrote in message
...

Many thanks for these two useful postings. The information I really need
in addition to this is which tube line interchanges are best avoided
because of those LONG walks along tunnels. Sometimes it seems like one is
walking underground to another tube station!


In some cases, you are.

Without getting into the detail, all the lines were conceived, and mostly
built, as entirely seperate entities with their own stations. During the
interwar years some joining up took place and a few stations were replaced
with another nearer to that on another line whilst in other cases
underground connections were built.