There were lots of these around one of my tubs today. They looked like a cross between a wasp and a fly, they were smaller tho.
(http://i7.photobucket.com/albums/y257/jesssands1/2013-08-25171205_zps92fc0c99.jpg) (http://s7.photobucket.com/user/jesssands1/media/2013-08-25171205_zps92fc0c99.jpg.html)
It's a hover-fly (Episyrphus balteatus) which are abundant, widespread and swarm on nectar-rich flowers.