I've had this photo for years, having bought it at an aviation fair ages ago. I've bought it for the U-2 but when I dug it out years later I realised that there is a VC10 in the background.

I've tried to create a close up of this part of the image but I just cannot make out the registration. More importantly, where is this? It seems to be a very specialised hangar modification to enable the front of a VC10 to fit inside, surely this had a purpose? Also the aircraft seems to be missing the titles along the top of the fuselage.

Anybody with an idea? What was happening, where and when?