I'm experiencing the same issue.
If I try and use webmail, often the page fails to load at all and it tells me to try reloading. When it does load, it's really slow to load in and it won't show any emails; it just shows a loading icon where the email list should be.
When using an email client, it connects to the server, then often hangs part way through the "receiving list of messages from server" stage. Sometimes it times out. Sometimes it eventually completes and I'm able to receive any new emails.
Something is definitely not right. I'm in the ST17 area and there was work done in the area to fix an email issue that started yesterday, which was completed earlier today. I was not having any issues with emails during the time period where there was supposedly an issue - it's only since the engineers supposedly resolved that issue that I've been having problems.
EDIT - I am not receiving email now. The process appears to complete and it says "no new messages", but I've sent myself 3 different test emails from 3 different accounts and none of them have been received.