Butterfly identification please!

Hi all

Saw an unusual (for me!) butterfly at Warren Gorge, Essex today. Had never seen one before (I've spent many recent years in Scotland). I hunted through my books, but couldn't source it at all.

The pic in the link below matches the sketch I made when I got home. The butterfly was very small and delicate looking. In flight it appeared to have semi transparent wings. However, zooming in with bins as it sat on a leaf, the non red bits looked black.

http://www.bbc.co.uk/essex/content/image_galleries/june_2007_gallery.shtml?1