Mottle-Winged Fly

I noticed this rather striking little fly on my daughter's bedroom window this morning.  A search of images on the web suggest that the wing patterns best match those of Tephritis matricariae a gall fly (family Tephritidae, order Diptera).

[Note added 2011-11-22: This is actually Tephritis praecox (Diptera: Tephritidae).  Identified by 'saeed' and 'nosferatumyia'  here.] 

This specimen is a female, the side view showing a large ovipositor:

Photos taken in Reading, UK, on 2009-07-21.