The first time we saw this insect, we thought it was a bee due to its colour. I posted photos of this "bee" on Instagram a few times, and was told that it is actually a fly. Yup, it's a hoverfly, also known as flower fly, which are frequent visitors of flowers in the garden. Well, at least it's much more good looking than the common house fly. The colors are quite pretty - purple face with bright yellow body and black stripes running across.
Judging from photos online, this is the Marmelade Hoverfly (Episyrphus balteatus).