That's Long-Tailed Blues (Lampides boeticus) and Common Blues (Zizina otis labradus - aka Zizina labradus labradus). In the past there have been many, but not this year.
It is my belief that the lack of blue butterflies is due to over-zealous people trimming along the sides of roads where longer long grass and, more importantly, the tiny Birdsfoot Trefoil plant grows.
BIrdsfoot Trefoil is the host plant for Blue butterflies so, with no plants to feed upon nor lay their eggs on, the butterflies are just not there.
Today, however, I saw three blue butterflies (yes, a whole three) in areas where, up until one or two years ago, there used to be dozens.
At this rate there might soon be none whatsoever.