A lockable overshot assembly for releasable connection to a spearhead point of a component part of downhole drilling apparatus, the assembly comprising: an elongated body having a head; a pair of lifting dogs pivotally mounted at the head, said lifting dogs having respective first ends configured for releasable latching of a spearhead point therebetween and respective second ends opposite said first ends; said lifting dogs being pivotally mounted at the head at a pivot location axially intermediate said first and second ends, said first ends being pivotally moveable toward each other to a latched position such that the spearhead point is latched therebetween and are pivotally moveable away from each other to a release position such that the latched spearhead point is released; characterised by: a locking arrangement mounted at the head and engagable with the lifting dogs at a region axially between the respective second ends and the pivot location, the locking arrangement configured such that in a locked state the lifting dogs are locked in said latched position and in an unlocked state the lifting dogs are allowed to move to the release position wherein the locking arrangement further comprises: a bore extending transverse through the head and positioned axially between the respective second ends and the pivot location; and a pin received in the transverse bore, the pin being movable transversely between the locked state where the pin is between the lifting dogs and prevents pivotal movement of the second ends of the lifting dogs toward each other and the unlocked state where the pin does not prevent pivotal movement of the second ends of the lifting dogs toward each other, and wherein the head further comprises a detent arrangement selectively engaging the pin for releasably holding the locking arrangement selectively in the locked and unlocked states. an elongated body having a head; a pair of lifting dogs pivotally mounted at the head, said lifting dogs having respective first ends configured for releasable latching of a spearhead point therebetween and respective second ends opposite said first ends; said lifting dogs being pivotally mounted at the head at a pivot location axially intermediate said first and second ends, said first ends being pivotally moveable toward each other to a latched position such that the spearhead point is latched therebetween and are pivotally moveable away from each other to a release position such that the latched spearhead point is released; a locking arrangement mounted at the head and engagable with the lifting dogs at a region axially between the respective second ends and the pivot location, the locking arrangement configured such that in a locked state the lifting dogs are locked in said latched position and in an unlocked state the lifting dogs are allowed to move to the release position a bore extending transverse through the head and positioned axially between the respective second ends and the pivot location; and a pin received in the transverse bore, the pin being movable transversely between the locked state where the pin is between the lifting dogs and prevents pivotal movement of the second ends of the lifting dogs toward each other and the unlocked state where the pin does not prevent pivotal movement of the second ends of the lifting dogs toward each other, and wherein the head further comprises a detent arrangement selectively engaging the pin for releasably holding the locking arrangement selectively in the locked and unlocked states.