Urban Wildlife: You'll know what this spider did this Summer

Look what I found this morning in the back-garden. The spider is wrapping some more yarn around this poor fly. If anyone knows exactly what's going on, or which species of spider this -- it will really help if you leave a comment.

The other thing of interest for me was that this is my first video with my new Samsung S6 -- the quality is remarkable (the one uploaded here has been compressed) -- I will upload the original on youtube soon. The ability to focus on this tiny spider really spell binds me to the advances in the common camera-phone :)