Gap in middle but ok at top & bottom

[Globalhelicopter]

At the hinge side of my double glazed window, there’s a gap between the seal and the window casing, letting in a draft. It’s fine at the top and at the bottom. I can see outside through the gap so it’s not sealed, either internally or externally. The gap tapers off to a tight seal both up and down towards the two hinged corners. Any ideas how to fix please?

 

[^woody^]

Wedge the frame out

 

[ronniecabers]

sounds like the window frame has been overtightened to the wall, and pulled over , as Woody suggests , unscrew and see if you can get a wedge in there. However a picture posted up might show the isuue is something different, Pictures from inside and out if poss, need context of positioning so not too close up!