Elongated bright light seen in a cloudless sky

I am totally open minded as to what the bright object in the picture might be. This was taken over Chipping Norton UK looking west at around 11.30am Sat 13th July 2013. I was photographing the landscape, and didn't see the bright object till the picture was loaded into the iMac. The picture was taken using a zoomed iPhone 4. I would much appreciate the views of anyone familiar with this kind of picture. All I can say is I really don't think it's an airplane in the normal sense of the word. Had it been a jet aircraft there would have been the familiar engine sound, but apart from some light road traffic noise, I heard nothing. I hope this is of interest.