So yesterday I went to lock my car, put the key in the drivers side lock, turned the key and it kinda clicked then nothing. The key just turns in the lock but doesn't lock. The passenger side still locks all the doors including the drivers door. So striped the door today to find the problem/ fix it and found this

The bit circled red is the part of the lock on the handle, that turns but, the bit circled yellow is the part going into the lock, this doesn't turn. What wrong?? Is it snapped? Do I need a new lock?.
Cheers
Josh