So, although this isn't really a serious issue, I do find it quite irritating!
I use Outlook as my mail program on my desktop, for both my Ntlworld and Gmail accounts. Occasionally, I add a folder to my inbox to store emails temporarily. When I no longer need that folder, I delete it on my desktop PC. My problem is, that when I check my mail on my iPhone (or iPad), through the Apple mail app,the folder still appears, although now greyed out. I cannot find anyway of deleting the folder from my Apple devices. This happens to both accounts.
I have tried logging in online directly into the servers, but the folders do not appear there at all, just on the Apple devices.
If anyone has a brilliant idea to enable me to delete these folders from my iPhone/iPad, it will be very gratefully received.