In message , Richard
J. writes
I still don't see why they didn't route it as a new tube line from
Paddington to Liverpool street via Charing Cross and Temple -
reusing the old Jubilee line route and Aldwych branch of the
Piccadilly
where possible.

Well, for a start, the Jubilee/Piccadilly tunnels aren't big enough!
Anyway it's a bit late now to start debating the route all over again.

Also, that route (Aldwych and Charing Cross) is currently earmarked for
an eventual DLR extension...

--
Paul G
Typing from Barking