In the Classic webmail you would mark an email as Spam and two things would happen. The email would be put in the Trash folder and the personal Blocked Senders Filter would be updated to block the sender.
On the TalkTalk Mail platform it's a bit more subtle. The Spam marked email is put in to the Spam folder and the TalkTalk Cloudmark Authority Engine is notified that you've marked an email as spam.
Cloudmark is the network based spam filtering that gathers information from users and other external information to be able to identify spam, primarily from a content analysis, and to block that spam on the network for the benefit of all users. The one thing it might not do is provide an immediate block for a specific sender. The number of mail users reporting the spam needs to get over a trigger threshold.
You can select an email and use the Mark as spam selection on the toolbar or in the drop down more actions menu within the email display. Please do that for real spam as that's helping the TalkTalk blocking filters learn to identify spam.
You can use Filter Rules to reject emails from a specific sender. Select the email, select the More actions menu within the email display and select Create filter rule.
Give the rule a name
Decide if you need multiple conditions to apply
The subject title is included by default If discarding / rejecting the sender's email is required regardless of subject then Select the dustbin icon for the 'Subject' condition
Add an action In this example, Discard or choose Reject with reason - add the reason in the text box
Decide if you need other rules to run (or untick Process subsequent rules)
Select the blue Save button
You've now prevented the sender's emails from arriving in your Inbox.