I got the impression that no one in BT customer support knew this until I made a huge fuss when I got back from Spain last December. The problem for us is that I guess most people use voicemail so there is no incentive for BT to rebuild their platform to correct the problem.
I even tried to record a number unodtainable tone as a message but the system wouldn't accept it, too clever by half.
I cannot understand why this problem has been marked as solved.
It's not what you wanted but your initial question has been answered accurately. That's the sense in which it's been marked as solved, so that anyone else with the same query can readily find the answer.
Sorry, but that just adds insult to injury!
The problem has not been solved, denying that there is a problem is just a cop out.
Someone made a mistake when the voicemail platform was built but instead of fixing it we are being told that it is a feature.
Can someone please escalate this and open a complaint.
The voicemail system, when roaming, is not suitable for purpose.
Surely it could only be classed as a fault if a specific feature dididn't function as it should. If a service doesn't offer a specific feature that you require, then the solution is to use a provider that offers the features that you require.