Tim Watts wrote:

Really is time they removed this archaic practise of holding the line
open until the *caller* disconnects. I thought it silly in the 1970s,
even knowing *why* it was done.

BT are in the process (maybe complete by now) of reducing the time to
clear a call to a few seconds ...

http://www.openreach.co.uk/orpg/home/updates/briefings/wholesalelinerentalbriefings/wholesalelinerentalbriefingsarticles/wlr00314.do