You don't specifically but I surmise this is an alias of a blueyonder address. In which it cannot be deleted without deleting the main address that it is branched off. Aliases share the same mailbox and password as the main address. The best thing you can do is simply not to check it.
If is it simply an additional e-mail address then it should be possible to delete it in My Virginmedia.
Superuser 18/19. Use Kudos to say thanks Tick an answer as "helpful" only when the problem is solved Please don't send me private messages unless I ask you to. I do not work for VM. The advice I give is based on my best understanding of VM policy and practice. You rely on it at your own risk.