British Telephones (Bob’s site)
Sam’s Telecomm Pages
Light Straw TEC [Some sections are awaiting updates, but book publishing currently takes priority.]
BT Archives (Holborn)
BT Digital Archives
PO Architecture
The Postal Museum
The Great Britain Philatelic Society [Lots of GPO resources.]
GBPS: UK POs by county (finder)
The Letter Box Study Group
The Handwritten Letter Appreciation Society (THLAS)
More…
Telephone Exchange Projects:
Lisa Kinch PhD Studies
Simon’s TE Pages
Dan’s Microwave Sites
Cold War History:
Cold War Civilian Communications (Ring Bell)
Modern Telephony
BT Digital Voice