View is distorted

What have I done to Blender and how do I fix it? Screenshot attached.


Number pad Key5 (ortho/persp toggle).

You seem to have entered a very low value for the lens of the 3D view.
Press N to displays the properties, go to “view” and check the lens value which is 35 by default.

Yeah, this was it, I’d managed to set Lens to 1. Thanks!