It's actually a brand new corded phone. I was plugging it in to test it worked. I'd only brought it because we managed to throw out the old phone as it had ended up in a box of stuff to be dumped. Even though we don't ever use the land line I always want to have a traditional corded phone in case of emergency.
I made the call to BT from the test socket. There were points in the conversation with BT when the noise went completely, and then it returned, sometimes at a minimal level, other times very bad. At least the operator could clearly hear it, so it made the call go very smoothly, which hasn't always the case when contacting BT in the past.
Noise on the line had been a problem a few years ago, so it's a little irritating that it's returned. I know the wiring in the box on the exterior wall of the house is less than optimal, so that may be something BT have to properly sort out this time, but it could also be nothing to do with it.
