I had this problem with a mondeo yesterday. Only way to know for sure is to back-off & disconnect the handbrake and check all the parts invidually. Check to see if the actuator on the rear of the caliper isn't seized. Then check to see if the caliper slides are free moving, the piston in the caliper and the pads in the carrier.
If it's all free you're looking at a handbrake cable.
__________________
|