Abstract: An apparatus configured to a downhole tubular to a pump. The apparatus comprises: a body portion having a bore; a locking assembly comprising at least one locking member pivotally mounted to the body portion so as to permit the locking member to be pivoted between an open position in which the downhole tubular can be inserted into the bore of the body portion, and a closed position in which the locking member engages the downhole tubular so as to lock the downhole tubular in the bore of the body portion. Fixing means is provided for fixing the looking member in the closed position. A method of drilling a wellbore using a borehole casing.