How to open the bonnet when cable is broken or jammed?

Hi,
Can anyone out there help me to get my bonnet open?
Have removed the cable from the lever inside the cab and tried holding the sleeve with one pair of pliers while hauling on the cable with another pair, but without any success.
Suspect the cable may have become disconnected at the latch end, but I'm not sure what's happened.
Is there any way to access the latch and open it without the cable?