No ‘Delete’ link showing for a WordPress theme?

WordPress Themes

Within WordPress admin, you can normally delete a theme from a site by clicking on the theme, within Appearance->Themes, and then clicking on the ‘Delete’ button in the bottom right hand corner of the pop-up window.

For obvious reasons you can’t delete the active theme, so if you want to delete that then you’ll need to activate another theme first. However, it’s important to note that you also won’t see the ‘Delete’ button on a theme if the active theme is a child of that theme. So for example if the ‘Ingham Creative’ theme is a child theme (see https://codex.wordpress.org/Child_Themes) of ‘Twenty Fourteen’, then I can’t delete ‘Twenty Fourteen’ whilst ‘Ingham Creative’ is the active theme, or unless I change ‘Ingham Creative’ to use a different parent theme.