Adults of the Hornet Mimic Hoverfly can reach 2 cm in length, and it is the largest hoverfly species in the UK.

The Hoverfly mimics the Hornet both in size and in appearance, and even makes a similar buzzing noise while flying, but it is absolutely harmless to humans.

Taken in my garden yesterday on one of my Buddleia bushes. Both images are cropped as I was using my 40-150mm zoom lens, so I wouldn't frighten it off.