They seek him here...

 

It's possible to spend all day in a favoured iris locality and completely miss his imperial highness. We've all done it!

From The State of Butterflies in Britain and Ireland, 2006.

For probably the first time ever, we've collected on these pages the distilled experience of generations of iris watchers. Follow these hints and you will dramatically increase your chances of seeing this elusive butterfly, but remember, the Emperor offers no guarantees!

Good luck!