Size up to 25mm with a hairy body resembling a bumblebee. The body is typically brown and relatively uniform in colour (c.f. Bombylius discolor). The wings are long and narrow, often held outstretched at rest, with a black front edge. 

Bombylius discolor

If you can observe the difference, please record whether the fly was male or female. Males' eyes touch on top of the head, females' eyes are widely separated. Males tend to peak two weeks in advance of females and it would be good to get more supporting data for this difference.

Gardens and hedgerows where it basks in sunny spots.

Spring.

The larvae are parasitic, typically preying on the larvae of solitary bees. The female lays her eggs near the nests of these bees, and the larvae then invade the nests to feed.

Common and widespread in Britain.

Common in Leicestershire and Rutland.

Dipterists Forum: Bee-flies in genus Bombylius: https://dipterists.org.uk/sites/default/files/pdf/Bombylius%20ID%20guide.pdf