Abstract: A downhole tool, such as a safety valve or a stand-alone nipple, has a tubular housing. An axially extending bore is provided in the wall of the housing. A radially extending recess is provided in the internal bore wall of the housing, encompassing the axially extending bore, and a control fluid pipe is passed through the bore and the recess. A cutting tool is mounted for radial movements in the recess and is actuated by downward jarring forces imparted by an auxiliary tool. The control pipe is severed by the cutting element and the lower severed end portion of the control pipe is concurrently crimped to close such end portion.