A trick I learned to deal with this very thing was just to attempt to call the local time/weather number after getting my dial tone back. That said, with far-s

A trick I learned to deal with this very thing was just to attempt to call the local time/weather number after getting my dial tone back. That said, with far-side supervision, I suspect that the call would actually time out after something like 20-30 seconds of either party hanging up. I'd just make it a habit to go put the kettle on and make some tea before placing another call. If the call doesn't time out, well, it's time to ask BT some hard questions as to why they're allowing that sort of nuisance on their telephone network. AT&T managed to get rid of it here just fine.