On 8 Jan, 18:35, "Dave Plowman (News)" wrote:

Of course there are - the underground cabling wasn't replaced for
broadband, and some is pretty old.

Not the local loop, so not especially relevant for broadband, but an
awful lot of cable _was_ replaced for digital telephony (i.e. into the
local exchange) and this was at lower data rates than we currently
expect from broadband (2 MBps and up). Some of this was to avoid old
connectors, some because the cable design itself changed (pair
conductors were separated into D-shaped groups within a cable, with a
screen between).

The sorts of bitrate we routinely push down phone cables today owes as
much to demonology as it does to Nyquist. I've never understood or
trusted it.