UPDATE: Since writing this article, BT have moved off the Yahoo platform (see: www.bt.com/newemail) – I’m unsure if the same issue is apparent for BT users, but the same issue exists for Yahoo as far as I know.
If you are a BT or Yahoo email user, then you may notice occasionally that your email takes an age to arrive. Sometimes you may even discover that an email someone sent you you has never arrived. If you experience this, here’s a bit of an explanation as to why this may be happening…