Anyone know what's going on here please

I've had a look at the adjustment of the handbrake the 13mm nut on the handbrake and it fully adjusted to the hilt even a long reach socket won't go on anymore. Handle gets around 3 clicks and feels good but is doing nothing at all as in wheels are turning, I can push the car with the handbrake on ..
What's the next I should be looking at please .
Any help would be great .

@timbo
You were bang on , thanks for that .
Adjusted the calipers , they were wound out too far .
I now have a working hand brake ..