Then after you are sure you will NEVER need it again, you can delete for yourself from the primary billing account, select My Profile >> Manage accounts tab
I recommend deleting all emails and contacts via webmail first, and after the deletion process, double-check the mailbox is gone from the VM servers by running the address through https://mailtester.com. Then you can be sure it is completely finished.
If the address is the primary email address, it cannot be deleted unless you are no longer a customer - and then the VM Forum Team will have to get involved. Wait here and someone will get your personal details by private message.
Re: Virgin media email has been hacked - need to delete
OK I have deleted all the contents from my original email account, I have changed my original username and I have setup a couple of additional accounts but in My Profile I still have the original email address (which I wish to delete) and the same address as an alternative with no option to delete or change either.