My own theory, for what it's worth, is that the third party organisations which ran BTs Indian call centers sold or are still selling the information they used to hold.
I have mentioned this a couple or three times on this forum in the past in the expectation that someone from BT would offer an assurance that this was not the case but so far no one has which only serves to convince me that I've hit the nail on the head.
Perhaps this time one of the mods will clarify but I'm not holding my breath.
