Thanks murrymints, but when I open the junk folder there's no "edit" to touch. So I can't put them in the bin. I have to open the Emails before I can bin them. Which of course isn't a good idea. Do you have any more ideas please.
Is this any help?
"Once you’re back in a folder or inbox, you can manage your email. Swipe
to the left on any of the messages in the list to reveal two icons: Move and
Delete (4.34). Tapping Move brings up your folder list, into which you can
move the message. Tapping Delete immediately deletes the message."