The present invention provides a method of determining the stuck point in a bore hole. The method employs a device, such as an inductor or coil (19), for writing magnetic marks into the bore hole casing. The device is incorporated into a retrieval tool (16) so that when a decision is taken to back off from the bore hole and recover any down hole equipment, the magnetic marks can be written on thecasing of the bore hole as the retrieval tool is lowered into place. As the retrieval tool is raised in the bore hole, lifting the down hole equipment towards the surface, the magnetic marks are readusing a three dimensional magnetic field sensor disposed either in the fishing tool or in the down hole apparatus itself.