A downhole jarring apparatus (10, 110, 210, 310) for use in jarring an object in a bore, comprising: a first jarring portion including a first impact surface (32, 158, 258, 358); a second jarring portion including a second impact surface (38, 160, 260, 360); a releasable axial connection between the first and second jarring portions (22,24) configured to be released upon application of a predetermined force between the first and second jarring portions (22, 24) to permit the apparatus (10, 110, 210, 310) to be configurable from a disabled configuration in which the impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) are prevented from being axially impacted together, and a jarring configuration in which the impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) are permitted to be axially impacted together and generate an impact force therebetween, and during reconfiguration of the apparatus from the disabled configuration to the jarring configuration upon release of the releasable axial connection initial axial engagement of the first and second impact surfaces generates an impact force therebetween, wherein the releasable axial connection is resettable such that the apparatus (10, 110, 210, 310) is reconfigurable from the jarring configuration to the disabled configuration to permit the apparatus (10, 110, 210, 310) to be resettable, and wherein the apparatus (10, 110, 210, 310) further comprises a rotatable jarring arrangement (37, 137, 237, 337) operable to translate a rotational drive movement to cause relative axial movement of the first and second impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) to establish axial impact therebetween when the apparatus (10, 110, 210, 310) is configured in the jarring configuration. a first jarring portion including a first impact surface (32, 158, 258, 358); a second jarring portion including a second impact surface (38, 160, 260, 360); a releasable axial connection between the first and second jarring portions (22,24) configured to be released upon application of a predetermined force between the first and second jarring portions (22, 24) to permit the apparatus (10, 110, 210, 310) to be configurable from a disabled configuration in which the impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) are prevented from being axially impacted together, and a jarring configuration in which the impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) are permitted to be axially impacted together and generate an impact force therebetween, and during reconfiguration of the apparatus from the disabled configuration to the jarring configuration upon release of the releasable axial connection initial axial engagement of the first and second impact surfaces generates an impact force therebetween, wherein the releasable axial connection is resettable such that the apparatus (10, 110, 210, 310) is reconfigurable from the jarring configuration to the disabled configuration to permit the apparatus (10, 110, 210, 310) to be resettable, and wherein the apparatus (10, 110, 210, 310) further comprises a rotatable jarring arrangement (37, 137, 237, 337) operable to translate a rotational drive movement to cause relative axial movement of the first and second impact surfaces (32, 158, 258, 358, 38, 160, 260, 360) to establish axial impact therebetween when the apparatus (10, 110, 210, 310) is configured in the jarring configuration.