Deleting administrator

Hi. I have two administrators listed under Users – one that I think was created when I first set up my website (automatically, by default? I can’t remember), and a second administrator I created yesterday. Both are in fact me. I’d like to delete the first administrator, since the username is an email address, which I don’t consider safe. However, it only allows me to View or Edit the entry, but not Delete it.

How can I delete it?

I thought that by creating a second adminstrator (as I did yesterday) with a different email address, I could then delete the first administrator (this was advice given elsewhere on the internet) but it hasn’t worked.

Any advice would be greatly appreciated!

Many thanks, Alex.