What I think is a male Blepharipa schineri (Diptera: Tachinidae). Identified using Chris Raper's and Matt Smith's revision 5c of Belshaw's 1993 Key which was distributed for their Tachinid Workshop in February 2014. I include a few more photos as evidence for this identification.
Details of the face:
The hind tibia has a Sturmia bella-like comb of anterodorsal bristles:
The middle tibia has 3 anterodorsal bristles (Sturmia bella has only 1 or 2):
Tergites 1+2, 3 have no median marginal bristles (in Blepharipa pratensis they do):
Specimen taken in Whiteknights Park, Reading, UK, on 2014-05-09.